I once couldn't sleep on day for some reason, decided to play TF2 to pass the time after 36 hours of no sleeping (didn't want to go to bed at 5pm), I promptly started TF2, joined a public server and realised that the only class I had the mental capacity to play was the engineer.
I turned my PC off and read a book.
In all honesty though if you're getting tired to quickly after around 9 hours of being awake your diet may suck, eat better.