I had very early Covid and never felt well after that.
Covid affects your immune system and you can later get more than one syndrome/disease.
My labwork showed very high platelets and I was diagnosed with ET, Essential Thrombocytosis. Meds brought my numbers closer to normal.
I still felt terrible when I stood up, heart racing etc and after 2 yrs of this I saw a cardiologist. My pressure changed 30+points from sitting to standing and he diagnosed POTS, Postural Orthostatic Tachycardia Syndrome. I’ll start a 3rd med because the first 2 meds haven’t worked.
Labwork doesn’t diagnose POTS - all normal.
There is a 15% rise in POTS since Covid.
My doc said I didn’t need a table tilt test because my diagnosis was obvious…
You could have many things but read up on POTS symptoms and it’s good you’ll have the table tilt test.
Good luck!