Hi Pj and welcome. I've been lucky and have only had one big fall since having fibro (knock on wood) but I have had many close calls. When I get over tired I feel like a zombie and it is an effort to do anything, that is when I hit the couch for awhile. I have passed out and had many times when I've almost passed out from having stomach cramps which they still don't have an answer for, I had some test last week but don't have the results yet. It could be vasovagal nerve syndrome for me. It causes a sudden drop in BP. Since you have had so many test done maybe it is part of fibro, who knows.
I'm glad you joined us. Read the fibro 101 thread, first on first page, it contains lots of great info.
luv and hugs
Forum Moderator Fibromyalgia
Fibro,Sjogrens, Anxiety, Gastroparesis, IBS, Gastritis, Allergies, High Blood Pressure, Low Blood Sodium and Osteoarthritis
Amitriptyline, Celexa, Xanax, Synthroid, Zyrtec, Micardis, Spironalactone, Tylenol, Reglan, Lidoderm Patches and Tramadol
Co Q 10, Super B Complex, Extra B12, Multi vitamin