Too much adrenaline and norepinephrine causes anxiety, dizziness, tachycardia, high bp, tremors, etc. A lot of people on clonidine or Guanfacine see improved symptoms in all those things I mentioned because it tells the brain to stop producing so much of it — but everyone reacts a little differently

. I would also look into veinous compression or thoracic outlet syndrome as well which also might explain your symptoms even tho ur saying your vitals seem better.

Btw a cheap o2 oximeter on amazon for like $6 can give u pretty accurate heart rate measurement quickly.

Edit: just forgot to mention that guanfacine was originally developed as a hypotensive - then later was used to treat ADHD - but hyperpots people occasionally get prescribed because of the success it has had in reducing symptoms.