I think I'm suffering from depression but with anger as well

Ever since my friend committed suicide in February I've been feeling incredibly bad but this isn't new to me. For my whole life I found it very hard to cope with people. Especially when I moved to Ireland, I have maybe three friends and the only one I feel comfortable to confide these dark feelings in is all the way in America. I just go through stages of not wanting to talk to anyone ad getting upset really easily or crying over nothing. I'm scared I have a chemical imbalance in my brain that is just going to make everything seems sucky forever. Ever since my friend died my sadness occasionally turns to anger. My friend was a homosexual and was bullied till she died for it. Now whenever I see some Christian quoting the bible and saying homosexuality is wrong I feel this anger that I've never felt before. It got so bad the last day that I was screaming at some jehova's witness guy. I've tried counting back from ten and stress balls but I just can't let it slide these days, it's like i'm not in control of my body. I've been bullied for a solid five years having kids cut up my bags and books and put them in the sink etc. Back when School was still on a girl who's used to bullying me tried to cut the straps off my bag while i was walking. One thing led to another and in seconds we were having a fist fight. I barely remember it I was so furious. I don't hit people, i endure, this isn't me and i'm scared of what's happening to me.