How should I behave at work?

I've been to work every day for the last 5 months without missing a day, despite the physical strain. I've been suffering from depression and have been through a breakup. Today I had a big argument with my father. I suspect he's a choleric person with aggression issues. I just called work to say I wasn't feeling well as I wouldn't have had the time anyway. Then they said I needed a doctor's note. It was only about working 3 hours after school. Now I'm driving to work for 90 minutes because I can't make it in time. I feel so ridiculous, my face is full of tears and I don't know how to explain this at work, I don't feel like talking to anyone there. Does anyone need advice? It's taking such a toll on me physically. I'm always under so much pressure, will I say the wrong thing, will my father lose his temper or will I do the wrong thing. It's depressing and burdening me so much. He said if I don't like it I should move out. He would never have said that before. But without money, it's not feasible anyway. I feel alone and can't do it.