If you feel you are about to be fired, you might as well stay, unless you find something to move to immediately. If you quit, you get no unemployment insurance. If they fire you, you can collect unemployment until you find something else. So, if it were me, I wouldn't quit unless I had something else lined up. Go ahead and start shopping for new jobs, there is no better time to find a job than when you currently have one.
I agree with DD. Stick with it knowing that you can quit and any time if he really pisses you off. If they lay you off, you may get some severance and are entitled to unemployment benefits to bridge you until you find a job you really like. If you are graduating for in December, it is also a good time to start job hunting.
I was working and going to school at the same time too (and raising children), and it was hard to find time for a proper search with everything. Quitting your job will give you an extra 8 hours a day to look for work in. Of course, you could also not quit, and still devote those 8 hours to looking for work.
a lot of the problems started when i told them I was going to finish grad school and would have to take off a cpl hours to attend my classes, after that it kinda spiraled from there. I even offered to work an hour early each day to make it up. So my dilemma is even if I wanted to find a job, it would have to be part time because of school. Anyone hiring part time accts/bookkeeper with 3 years experience (lol)?