That's a hard thing. I'm a theatre design major and I'll be honest, I think only law and med students parallel the work hours that we keep. Many nights I don't even get to sleep because I won't meet a deadline...or if I do, it's only for a half hour or so. Add to it this semester, my last, 42 hours of work work a week and I'm basically drowning already. It's rough, but you have to do what you have to do.
I don't say this to minimize the impact of your schedule at all, but more to say, 'Trust me! I'm right there with you...'
My advice is try to schedule your time out. Give specific amounts of time to work on things and schedule plenty of short breaks. Also, schedule time to do some social things with friends. Unfortunately, if these things are very impromptu you may run into trouble. For me, I try to schedule things out. Do I stick to it? Not really, but it puts everything into some sort of perspective. I often find that I don't have enough time to allow for my projects. Sadly, there isn't much to do about that, but the best I can do. For others...they choose to stay sane by getting drunk. A drink or two is fine, but I don't think drunkeness is a productive habit to be in though...