Ultrasensitive PSA test results: Should I be concerned?

Im tring not to panic at this point, I have a retest in 10 days and will
proceed from there. My psa 3 years ago jumped up over normal range 3 years
ago, then after retest it went back to 2.1. If its still elevated after
retest then they will do an mri.

@ginger38314 Best wishes!

@ginger38314 Thanks for the reply. The walk and gym activity should not have influenced your PSA level. Again, some bike riders riding longer distances and more often can see rises in PSA due to the physical pressure of the weight of their upper body resting on the narrow bike saddle that presses up on the perineum and prostate. And of course "BPH" can cause elevated PSA. You mentioned that your urologist said that your prostate is very enlarged. That may be the main source of the newly elevated PSA level. You should have the other symptoms of BPH as well: difficulty urination from "occasional" to "often", to "perpetual." Did your urologist put you on alpha-blockers or 5-alpha reductase inhibitors? Those are used to treat BPH and might help lower and stabilize your PSA levels.
I am a former Director of Clinical and Anatomical Laboratory Services ("The Lab"). There is a test that can be influenced by physical activity, but PSA is not one of them. There is an enzyme called Creatine Phosphokinase (a.k.a. "CK" or "CPK"). There are three "isoenzyme" forms of CPK, each having origins or more dominance or prevalence in certain tissue. It is predominate in Brain and Muscle tissue. One isoenzyme is CK-BB ("CK-1") is found in the brain. Brain injury and neurological diseases see increases in CK-BB. There is CK-MB ("CK-2"), found in the heart and measured when you arrive in the ER with a suspected heart attack. There is CK-MM ("CK-3") found in skeletal muscles. This is the form that will temporarily increase with hard physical exercise (walking, running, gym lifting). It is the most abundant of the three isoenzymes of the CK enzyme. A handful of other lab tests can increase with physical activity. There is another enzyme called Lactate Dehydrogenase of which there are five (5) "isoenzyme" forms. Two liver enzymes Aspartate Aminotransferase ("AST") and Alanine Aminotransferase ("ALT") can rise with excessive physical activity. Your Potassium ("K"), Urea ("BUN" test), and White Blood Cell ("WBC") count can also temporarily rise with excessive exercise in response to the stresses put on the body. They are an inconsequential response to physical activity.
So...that was a long-winded response to your offering that you took a long walk and went to the gym the day before you had your blood drawn for the PSA level. And BTW...no combination of any of the above tests being temporarily elevated will combine to cause a temporary or long-term increase in PSA. Sex and bike riding are the main factors. Either/both will cause a temporary increase in your PSA for upto 48 hours after. So...a man with an active sex life of "every other day or every third day, likely is walking around with a perpetually "slightly" increased PSA. The good news it is not related to him having prostate cancer. You need a positive digital rectal exam (DRE) and positive biopsy to relate elevated PSA levels to prostate cancer. By their '60's, most, but not all men, have cut back on long bike rides that might cause an elevation in PSA.
And, finally... In the "good old days" before the PSA test was developed as a reliable assay for prostate health, there was/is another test: the enzyme "Acid Phosphatase" that was an indicator of prostate issues. The PSA test has been the gold standard for assessing PSA health for the last ~40 years. The first PSA test was developed in the 1980's.
Hope this helps. Good luck to you.

Three years ago it was also elevated and I did the same routine extensive walking and weights afterward, on retest did nothing 2 days before psa dropped 2 points to normal, so I guess it was just a coincidence.