Long work hours + Lack of sleep + Things to do on the internet = falling asleep in your computer chair for 7 hours. Damn, I feel like I have a hangover, only without the beer.
You probably would have felt the same if you'd had the beer. It would have made you not tense and sleeping that way at the desk wouldn't have been so bad but then the actuall hang over would have gotten you. It's a catch 22