Haha, well you know my answer already. :P
Starting in January of my Senior year, I stopped being able to sleep more than like an hour or two a day(if I was lucky), and that continued for at least two months, if not more. I also got a serious case of food poisoning (Or stomach flu, or something else... I don't even know.) not long after that honestly could have killed me, since I was under 100lbs by the end of it, and I'm 6 feet tall. So, with all of that, by the end of the year, my GPA had dropped from 3.7 to 3.1, and I never even finished my senior project (They let me graduate anyway though.) Still haven't gotten to college because that screwed me up so much.
So yeah, two months straight... and that's not the only time I've had it for an extended period. (Although, now I sleep like 10 hours a day, lol.)