Have energy...then CRASH!

Yes that is exactly what happens to me. Energetic, do too much, then crash.
Your job is to figure out how many productive hours you have in a day and work within your limits.
Mine is 4, that's 4 hours to shower, eat , shop, talk to people, drive, work, basically use my brain or body, etc.
I can only do 4 hours total and then I have to rest the rest of the time. If I exceed that, I crash the next day and need to do nothing for at least a day but sometimes more. That is my version of pacing.
Good luck!

After a couple years of fatigue, I found the solution is to increase nitric oxide production that improves oxygen going to the tissues. Our nitric oxide production decreases as we age. I would suggest researching nitric oxide production foods and supplements.
I take citrulline and L-arginine with vitamin C each morning. That is major in my getting back to normal. If you are on meds, check to see if there is an interaction. In most cases, there is no interaction, but it is best to be cautious.
I will give a couple references from my journal:

Nitric oxide decreased levels may cause chronic fatigue. Low nitric oxide levels can decrease your body’s natural energy at the cellular level. This is a result of reduced circulation, reducing the delivery of oxygen and nutrients that your body needs.
https://www.medicinenet.com/what_does_nitric_oxide_do_to_your_body/article.htm
The mechanism of action that leads to the state of fatigue, or disabling exhaustion, linked to Long Covid which affects 1 in 3 people who are victims of the Sars-CoV-2 infection has been discovered: it is triggered by a deficit of arginine, an amino acid naturally produced by the body.
https://www.coronaheadsup.com/health/long-covid/long-covid-fatigue-caused-by-an-arginine-deficiency/
Boosting NO production 1. Have RAW greens at every meal or at least daily 2. Cooking and dehydrating destroy NO-building capacity 3. Accompany greens with a source of Vitamin C 4. Consume foods high in polyphenol antioxidants like dark colored fruit, (berries), red wine or grapes, and dark chocolate (65% cacao or more) 5. Include exercise in your daily routine, 30 minutes is recommended 6. Fish oil and other unsaturated oils boost NO production {or fatty fish twice a week instead of fish oil] 7. Refrain from using mouthwash since it can decrease NO production by at least 1/3
https://extension.oregonstate.edu/sites/default/files/documents/8836/asay-no-disease-handout.pdf
Note: High salt and high sugar can deplete nitric oxide production and should be avoided. Plan on a couple of months of diet and supplement adjustments to get to "normal", but it is worth the journey.
Good luck!

Thank you for your detailed report on the potential role of Nitric Oxide and Arginine in LC fatigue. And for providing those links to related sources of valuable information. Providing links to sources like those allows us (the readers) to evaluate the data and decide what action is best for us.

Two more causes of fatigue are B12 and folate deficiencies. B12 is difficult to absorb and is best taken in sublingual (under the tongue) form. If we do not have sufficient hydrochloric acid or intrinsic factor, the B12 is not absorbed and can lead to anemia.

Folate is in high amounts in food like lentils. Folic acid is the synthetic form that could create health problems.
Here are some links:

Two things need to happen for your body to absorb vitamin B12 from the food you eat.

Hydrochloric acid in your stomach removes vitamin B12 from the food it was in.
Vitamin B12 combines with something called intrinsic factor, a protein made by your stomach.
Vitamin B12 is then able to be absorbed by your digestive system.
https://my.clevelandclinic.org/health/diseases/22831-vitamin-b12-deficiency
Folate-deficiency anemia is the lack of folic acid in the blood. Folic acid is a B vitamin that helps your body make red blood cells. If you don’t have enough red blood cells, you have anemia.

Red blood cells carry oxygen to all parts of your body. When you have anemia, your blood can’t bring enough oxygen to all your tissues and organs. Without enough oxygen, your body can’t work as well as it should.
https://www.hopkinsmedicine.org/health/conditions-and-diseases/folate-deficiency-anemia#:~:text=What%20is%20folate%2Ddeficiency%20anemia,all%20parts%20of%20your%20body.

I can relate to your experience of intense emotions precipitating a crash. I’ve found that if I let myself get excited that this will cause a crash, more so than gently paced activity. So I watch myself: if I recognize that I’m getting excited I consciously slow my thoughts and emotions down and do some slow deep breathing. The other major thing which will cause me to crash is doing ANY activity in high altitudes. My gas exchange in my lungs is impaired since I got Long Covid 3 1/2 years ago. I live at 4000 feet above sea level which is stressful for me. If I travel to places at sea level I can breathe much better and walk around without crashing. Then back to our airport and I’m stressed just walking one block.

Thank you again for providing a detailed report — this time on two more potential causes of LC fatigue — and links to the related information sources.

After having long covid fatigue for about a year, I yelled at my family “I am tired of being tired”. Those words echoed back at me and I started to do research on what could be the solution. I would like to share my research and I would like to encourage all of you to do your own research and consider a few possibilities that could help you. I will give you some links to get you started.

I previously wrote on the importance of nitric oxide production and absorbing B12 and folate. They all assist in getting oxygen to the tissues. I will mention some more that could help. As usual, if you are on meds, check for interactions and use caution if you have diabetes.

From Cleveland Clinic: “Any condition that reduces the amount of oxygen in your blood or restricts blood flow can cause hypoxia. Your cells need oxygen to produce energy and help your organs and tissues to do their jobs. For oxygen to make it to the cells in your tissues, you need:
• Enough oxygen in the air you breathe in.
• Healthy lung function to get oxygen to your alveoli.
• Healthy heart and circulatory functions to get oxygen-rich blood to your tissues.
• Enough red blood cells to deliver oxygen.
• Tissue cells capable of using oxygen.
Low amounts of oxygen in the blood (hypoxemia) can lead to hypoxemic hypoxia, the most common cause of hypoxia. Hypoxemia can be caused by lung and heart diseases, congenital heart defects, and medications that slow your breathing. Traveling to a high altitude, where levels of oxygen are lower, can also cause hypoxemia.”
https://my.clevelandclinic.org/health/diseases/23063-hypoxia
DEHYDRATION CAN CAUSE FATIGUE AND THE SIMPLE SOLUTION IS TO DRINK MORE WATER. HERE IS A LINK TO AN ARTICLE ON EATING WELL TITLED “6 Best Drinks When You Need an Energy Boost” and the number one drink is water.
https://WWW.EATINGWELL.COM/ARTICLE/8038944/BEST-DRINKS-FOR-ENERGY-BOOST/#TOC-OTHER-TIPS-TO-BOOST-YOUR-ENERGY
CREATINE: Among the often-mystifying, extended effects of COVID-19 is post-viral fatigue syndrome, or (PVFS). A small new study finds that dietary creatine may help alleviate its symptoms.
The study found that taking dietary creatine for three months substantially improved feelings of fatigue, and by six months, had produced improvements in body aches, breathing issues, loss of taste, headaches, and problems concentrating — or “brain fog” — compared to people given a placebo.
https://www.medicalnewstoday.com/articles/can-creatine-supplements-help-people-with-long-covid
Taking high doses of creatine for a short period of time is shown to help older adults have more energy throughout the day.
In addition to fighting mental tiredness, supplementing with creatine can also help with muscle tiredness, particularly in your lower body.
https://www.webmd.com/healthy-aging/is-creatine-safe-for-older-adults
[My note: Carnitine helps the body turn fat into energy and decrease fatigue. ]
“The coronavirus disease is a viral infection that could induce different respiratory, gastrointestinal, and vascular problems. Evidence shows that many patients with the disease experience a long recovery period, and symptoms such as fatigue persist for several months after infection. Fatigue depends on a variety of conditional and physiological factors, and its exact molecular mechanism has not yet been elucidated; however, it is probably caused by cytokine storm, which can cause inflammation and anorexia, followed by muscle loss, weakness, and tiredness. L-Carnitine is a trimethylated amino acid that is structurally similar to choline and is needed as a cofactor to convert long-chain free fatty acids to acylcarnitine and transfer them to the mitochondrial matrix. Dietary L-carnitine supplementation successfully has beneficial effects on the energy metabolism of the cells and related mechanisms in regeneration of muscles. Since the beneficial effects of this medication in relieving fatigue caused by diseases such as cancer, MS, etc. have been demonstrated, it can also be considered as a potential option for relieving the fatigue caused by COVID-19. “
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8667465/
[My note: Ornithine, arginine and citrulline relate to nitric oxide production that improves getting oxygen to the tissues.]
Ornithine is an amino acid that is made in the body. It's not used to create protein, but plays a role in other processes. It can also be made in a lab.

Ornithine might help to increase levels of another amino acid called arginine.
https://www.webmd.com/vitamins/ai/ingredientmono-200/ornithine
Ornithine, arginine, and citrulline are the three amino acids involved in the urea cycle. Your body uses ornithine to make polyamines (which play a role in cell growth and proliferation) and the amino acid proline (used to make collagen). Preliminary evidence suggests that ornithine supplementation can improve athletic performance by reducing elevated levels of ammonia.
https://examine.com/supplements/ornithine/
How does HMB work?
So what can you do to maintain muscle health? That’s where HMB might be able to help.
HMB may act as a gateway to help keep your muscles in balance by slowing muscle breakdown. In fact, HMB has been shown to help preserve muscle mass in healthy older adults. Maintaining a well-balanced diet rich in protein and exercising regularly supports the natural balance.
“Levels of HMB in the body are significantly correlated with existing muscle mass. One thing we can do to benefit our muscle health is eat a good diet, including getting more HMB and keeping up with strength building exercise," points out Pereira.
How to Get HMB
Getting more HMB naturally isn’t always easy. In the body, less than five percent of all leucine is converted to HMB1. Even on a good day, protein-packed foods can leave adults coming up short.
Pereira agrees that meeting HMB goals through food alone is very difficult. "You'd have to eat around 6,000 avocados to get enough to get a few grams of HMB" she explains, "and I think you'd turn green before you got there."
https://www.nutritionnews.abbott/healthy-living/aging-well/why-hmb-is-important-for-aging-muscles/#:~:text=HMB%20may%20act%20as%20a,regularly%20supports%20the%20natural%20balance.
My note: I would suggest keeping a journal of how you are feeling and what you are trying. It can be very helpful to look back to where you were and how you are doing now and what helped you. I write my journals in Word and find them useful. Add links for any important info. Updating once a week or a couple times a month is fine but daily would be best, especially at the start. It can be a great reference in the future. It could also be helpful for your doctor.
Keep researching and trying what you feel is appropriate to get better. Remember that “normal” is still attainable. It is a matter of finding the right combination. For me, I have been taking all of the above. Good luck.

4 year sine wave with varying phase length....up down up down

I'm in the same situation, 4 hours, took me 3 years to get here.... I'm going to doctor next, ask for more bloodwork... I'm tired of this

Yes, hang in there...I am writing this after a 4 hour nap to make it through the day.