I have an MA, but I work at a coffee shop and for a promo company, and am in the process of getting a third job (and will still only be scraping by). That's the way of it now. A lot of people are in the same boat (many far worse!).
That said, I could not be happier about my position, because given the option of this or being back in school, I would take this 1,000 times over.
And it's not just that I had a particularly bad experience in graduate school, though that's certainly a part of it. Really, it's that school doesn't end. When I work today from 6:45am to 10:30pm, at 10:30pm I am done. Not so in school. There's always something more you should be doing. Even if all of your projects are finished, all of your reading is "caught up," there's more research you should be doing, more sources you should be investigating, more anything you should be anything-ing. The work of the graduate student is never done and he is never off the clock.
Add to this my general disdain for the work itself. I'm so sick of the bullshit. I never got to read about my interests because I was always trying to bulldoze through my reading for courses, courses that didn't really interest me at all. And, if I'm being honest, I'm just tired of academic work. Taking endless notes, comprehending and comparing theories, generating your own. Yeah, I guess I burned out.
So when I'm feeling sorry for myself because I had to work for the Camel job last night, and then pull a double today, I just remember how much better it is than the alternative. And then I can sit back and relax. Everything's coming up roses. =)