I'm super miserable at my job. School is stressing me out and I'm becoming very negative. What can I do?

I hate my job. Everyone here is fed up and the morale is so low that no one is happy. School is extremely hard this semester and everything that comes out of my mouth is negative. My birth control pills have turned me into a crazy woman I think. My fiance and I are fighting alot because he just doesn't understand what I'm going through. I don't even know what my problem is. I cry for no reason or I have outbursts of anger. Anyone have any advice before I ruin my relationship?