oh yuck! poor you! I had that a couple of years ago and it is the wierdest feeling ever.
I was sitting in a lecture at uni and all of a sudden I started to feel really hot and sick and like I couldn't stay awake and then I fainted in my seat! It was kind of embarassing actually. I never fainted again, but for months I kept getting wierd dizzy feelings and headaches.
I guess it is lucky though that it is not something more serious

Hope you are feeling better soon!!