to me this happened over a long period of time. a little over a year. before it hit. one day i was seemingly fine and the next, i felt drunk all day or like you feel when you get woken up really early and fall back asleep. i didn't know where i was. what day it was. what year. keeping up at school was insanely difficult.
reasons as i see it: Dehydration, i started smoking about that time. as a way of calming down from a build up of stress acquired from going as a server at an all you can eat buffet to a web designer. i was working with my head not my body. and the build up of stress Lack of physical activity Smoking = panic attacks that sent me to the ER where i was without warning shot up with an over dose of adivan (im hyper sensitive to medication) i blacked out and spent the next 5 months detoxing. that was fun.
then i started exercising more, started taking vitamins. and eating healthier. im almost over it. read more on wikipedia google Orthostatic Hypotension read up.
your body is in a constant state of trying to find balance and to maintain that it will cut off peripheral sub systems to protect the organism, you. the same reason why frostbite starts at your fingers and toes.
your body doesn't have sufficient materials to distribute or a means to distribute it. dehydration = low blood count = low oxygen = fuzzy head.
drink a whole lot more water and exercise. if you are already doing that exercise your brain there needs to be balance.
my problem was the big shift. i could complain about my job all day and get a work out. then all i did was think. it screwed me up pretty bad and i want to help if i can.