Fifteen years ago, I was hospitalized for ten days while they tried to figure out why I had developed extreme orthostatic hypotension (even lower than yours. I had spent three days in and out of consciousness on the floor of my living room unable even to stand to get to the phone for help). Had also fallen down the stairs more than once. When I finally got to the ER they even had trouble reading my BP.

By the end of that period of intermittent unconsciousness, of course I WAS dehydrated but that had nothing to do with the cause of my problem. I felt fine reclining (normal BP). but as soon as I tried to stand, I blacked out immediately (In the hospital, I was forbidden to stand.). Standing (with support - on both sides), also led to tachycardia. (Do YOU have tachycardia upon standing?). It was a terrible experience especially because I was mistreated in the hospital. They even tried to discharge me without a diagnosis!

I should have been diagnosed within minutes in the ER because it turned out my condition was the result of a new medicine (Nardil , an MAO inhibitor antidepressant) which , with the permission of my psychiatrist, I was gradually titrated up as needed. I guess the most recent 15 mg titration pushed me over the edge of getting this known side effect. One of the most basic question supposed to be asked (and checked) in the ER is what meds the patient is taking and whether any are new. (If so, they are to check whether it has any known side effects corresponding to the the patient's presenting symptom - for me orthostatic hypotension.). Dumb dumb dumb!! Their failure to follow ER protocol cost me $30K, and ten agonizing days of neglect and rudeness, until it dawned on someone to link it to that medicine.

In any case, I've taken this opportunity to complain about one of my all-time worst medical experiences (sorry for what may be boring) which I'm describing because it's a good example of what can cause your symptom. I was checked to rule out many other causes (EXCLUDING linkage to my meds!). It is infuriating that they are writing you off without adequate investigation. About your stomach pain, I don't know (unless you have internal bleeding there as blood loss can also cause low BP.) Do you have the low BP at particular times - for example, upon standing? Have you ever passed out? We really have to advocate for ourselves. Try not to panic, but DO persevere in insisting on a thorough evaluation.

(My treatment was discontinuing the causative medicine and being prescribed Florinef - a medicine that caused salt retention to deal with the dehydration (even though it was caused by that period without fluids.)

Wishing you all the best in arriving at a diagnosis and treatment.