the exact same thing happens to me.it freaked me out at first and i went to th doctor but they didn't know what was happening.it has been happening for a little over a year now and im not dead yet:rasta:.it still happens.i don't know about you but when it happens to me i usually pass out and fall down(somewhat embarassing)you should be fine if that it still feels like a headrush,beleive me i have been pretty out before.:thumbsup: but hey,if some how you find out what is causing it let me know would you:rasta: