So depressed about work I'm close to tears?

I don't know what to do. My situation is quite complex: I relocated with my husband and baby and started my new job in January, shortly after the death of my mother in law. So we've had quite an upheaval. I work as a teacher, have done for almost 8 years, and I hate it. My new school isn't what I thought it would be and I don't like my new colleagues, my head of department is moody and highly strung. Our main reason for relocating was so that my mum could childmind for us. Since we've moved, I haven't lived here for 12 years, I've found out what a heavy drinker my mum is. She drinks every night to the point where she can barely stand and wets herself on the sofa. I've had a word about the drinking and she's promised to stop. She hasn't had a drink now for about 5 days but I don't know how long this will last. I'm so exhausted from work and from worrying about my daughter's safety that I'm constantly ill. In a school you pick up bugs and viruses every couple of weeks anyway but usually I can fight them off. However, I had flu a few weeks ago which left me feeling drained. I went back to work earlier than I should have because I was so worried about having time off. This then resulted in a secondary stomach infection, so more time off, and again I went back too soon. Now I have bronchitis. Because this has been 3 separate absences I'm going to get pulled in for a meeting. I'm dreading this. I hate the job and want to quit but can't because of finances. Also in this current climate I'm lucky to have a job. I just honestly don't know what to do for the best. I'm not doing right by my daughter, I'm not doing right by my job and I'm not doing right by myself where my health is concerned.