I agree- go to the doctor if you're feeling that concerned about it.
A few months ago, I had some kind of issue where I woke up and was extremely lightheaded. Every time I lifted my head off the pillow, I would literally feel dizzy and just lay back down. I thought I was at the end of life or something. It was seriously scary. Did I go to the doctor, though? No. I wanted to see if it was a regular occurrence or a once in a lifetime thing. I was finally able to get up, drink my water and have breakfast. Well, it never did happen again. I have to attribute that to being dehydrated and probably not having a good dinner the night before, which probably made me hungry. All this probably made me dizzy. BUT- if it happened again, I would have hightailed my butt to the doctor- not went on bikeforums to ask for help!
See a doctor if you're that concerned!
koffee