I have a history of syncope. I passed out several times as a teenager and my doctor said my iron was a bit low. I have been taking supplement ever since. I passed out several years ago and was diagnosed with a virus. My doctor said I passed out because I wasn t feeling well. Just last week, I passed out again but the doctors were not able to determine why. Before I passed out, I started to feel sick to my stomach and then I got dizzy really quick. I also noticed that I had felt felt extremely cold for days before hand, then that day I started to feel really warm but didn t sweat at all. After I woke up, I started sweating a whole lot. It also took me a long time to recover this time. I had problems with my concentration, memory, and was clumsy for a couple days after. What could be causing my symptoms? What type of tests should my doctor run?