I also was diagnosed with Postural Orthostatic Tachycardia Syndrome (POTS) in 2009 after spending weeks flat on my back, not able to stand up without my bp dropping extremely low (unreadable on home machine) and heart rate raising over 30+ points just standing. It came on after a bad ear/sinus infection. Dr. said I had probably had it since childhood (have always been prone to faint) but the illness kicked it into overdrive. I was put on Midodrine and it was a wonder drug for me. I was able to go off the med after about 6 months and am ok. Still prone to faint with pain and have to wear HR monitor when exercising, but almost normal.

This episode occurred about 5 years after my RSD went into remission and I always wondered if there was any kind of connection.

Hope you can get your fainting spells figured out. As others have said, drink lots of liquid, increase salt, ( I drank low cal drinks with high sodium in them), and compression hose might help. They usually use a tilt table test to confirm diagnosis.

Deb