Work place hell

I hate my job. I wake up every day wishing I could just quit or that they would find some reason to fire me. I'm wondering if there's a way for me to quite my job and go back to school and get my BA in veterinary medicine without starving to death. If I didn't have kids, I'd have already done it. I have to find some way out of what has become my every day hell. I tried to get up with a positive attitude and find something that was good about my job but when every word you type makes you want to drive off a cliff, it's kind of hard to look at the positive.