It only speaks of increase diastolic pressure (bottom number) with slight increase in systolic (top number)...in relation to increased heart rate (which is POTS--postural orthostatic tachycardia syndrome).

Did you have any increase in heart rate? In POTS, you can have increased HR without drop in BP (like stated above from article)...but most common is increased HR due to compensatory reaction to drop in BP.

Did they check autonomic fibers with your skin biopsy?

Maybe you should have some autonomic testing QSART, tilt table, etc.