OP I do the exact same thing. Busy nights drive me crazy, even though the money is good.
I get myself in the mindset that "this isn't my career. It's just a job."
Then I'm less worried about it. If I make a mistake, it doesn't hurt like it would if I failed my dream job. Just relax while you can. Kick back and watch tv, eat something, just enjoy your free time.
You wouldn't happen to work at an Italian Restaurant do you? >.>