Lynette, your symptoms and journey sound so much like what I went through over 10 years ago! A tilt table test (and a test of catacholamine function in supine and after being vertical for 10 minutes) will help diagnose possible POTS — maybe “hyperadrenergic POTS”. Your doctors will want to rule out the ‘regular stuff’ (as you mentioned, you don’t want to miss pheochromocytoma or carcinoid cancer/ brain tumor, blah, blah, blah), so unfortunately, you have to let them put you through the ringer of normal tests first. I remember telling doctors it was if my ‘body was having a panic attack without me’. (I didn’t feel panicked or nervous, but my body was responding as if I was). Sound familiar? Please hang in through these tests, and I know folks here will all do what we can to speed up your journey to answers ASAP. Gentle hugs…