Freelance Animation: Balancing Work and Home Life

I admit it: I have a serious problem with disciplining myself to get my freelance animation work done within set work hours. I sleep when other people are awake, I'm awake when other people are asleep, and it's not unlikely for me to finish my work at 3a only to saunter off to the 24/7 grocery store for a supply run. You'd think this sounds like an ideal life, especially since I never miss a deadline on animation work - but these are bad habits that I really need to break. I never feel rested, I live on caffeine and junk food, and my weight yo-yos up and down because I exercise sporadically (although on the side, my World of Warcraft addiction probably doesn't help that). The trick is balancing my work and home life, and setting strict boundaries for both. And if I'm not that great at following my own rules...well, do as I say, not as I do.