I've been kinda light headed, what could it be from? (easy 10 points)?

well about 3 days ago i drank a lot of mt.dew and i usually dont have caffeine so the next day when i was off and on light headed i thought it was from that. but i am light headed off and on again today. both says i have been reading a lot but i dont know if that would contribute to it. I just feel like my head is a little heavier than usual and i feel a little woozy every once in a while. I was thinking it could be animea because it runs in the family and ive been prettty tired for a wile but i dont know. thanks!