I had several symptoms and was diagnosed with POTS
Postural Orthostatic Tachycardia Syndrome does NOT present in labwork and is hard to diagnose. You diagnosis might be different.

I had very early Covid, then Ling Covid and lost most of my immune system.
Next diagnosed with ET, essential Thrombocytosis- chronic leukemia.
Even after my platelets were lowered from 1.1 million to 600,000 I felt terrible and was diagnosed with POTS.

The long term effects of Covid are different for everyone.
Try to find a long Covid center. Mine wasn’t helpful but it depends on the doctor - nice telehealth appt with the doc, but not helpful.

Ask to be put on a waitlist for canceled appts with the cardiologist.
Keep a list of ALL your symptoms to show your doc.

If you have a pulse ox or blood pressure cuff, test yourself sitting quietly and again when standing or walking a few minutes. With POTS my numbers fluctuated 30 points. After a year from diagnosis my doc still hasn’t found the right combo of medicine to normalize my pressure.

Don’t be discouraged - it takes a lot of effort to be diagnosed and get the care you need. Don’t give up! We’re here for you.