Stupid Tired

Can someone please tell me why my toddler won't sleep? Sure, he stopped sleeping through the night at the age of 1 - but why is it he now has decided to stay awake for 2-3 hours each night? He isn't napping anymore, isn't he tired? I'm tired. Stupid tired. Want-to-cry-at-the-drop-of-a-hat-tired. Don't-really-like-anyone-tired. First to go is that damn toddler bed. It's cute but a pain in the ass. I think it's too small. If I get him a twin bed and he still doesn't sleep - I'm pulling a "ya-ya". People have been warned.