Should I quit my job?

Okay first off, I hate my job. I work as a waitress at two different locations (owned by the same people) and I’ve only been working there a month. When the owner hired me, I told her that I am going to be starting school on the 22nd of August and that I would need to cut my hours. Little did I know however, is that they have maybe five other people (between both locations) and I am the only one that switches between both places.
Well, the big problem is, is that my boss and the cooks (who pretty much work as the manager) have a problem with telling you if you did something wrong! I have to find out from my friend (who works there too) that I do all these things wrong, instead of telling me! Also, the cooks a liar and very misleading. He looks at the register (Mind you, I am new and was not properly trained) and just mentions that someone needs to go to the bank, takes the money and goes to the bank. I here then from my friend, that he “Asked me three times to go to the bank” and that I didn’t go. But that is only grazing the surface. I closed the place last night and forgot to get the trash out of the restroom and I hear from my friend that my boss saw that and now has a ‘list’ of things that she wants to talk to me about…
She is also apparently mad at how much I slashed my hours because of school…which is something I told her about before she hired me. I really don’t need this job (I have another) but I just like having the extra money.

So do you guys think that it would be a just decision to quit me job? Thanks.

Well…I’m off to work now… /: