Why am I here?

I’m a christian. I love God with all my being, but i always wonder to myself why I’m here. My life is a miserable wreck. I’m fat and ugly. I’m not “popular”. I have almost no friends.  My family is way messed up. My Dad doesn’t give a crap about me and my step mom is a snobby psycho. My sister is moved in with us for reasons I have no right to explain. My sisters daughter is everything I’m not and makes me feel jealous everyday, my little brother is a major douche bag and is probably going to end up caught up in drugs or something stupid, I have OCD, and I have an anxiety disorder. My life story has been very complicated. When my birth mom had me she was 21 and my dad was 42. Lovely right. He’s had more than one wife. I was taken away form my mom when I was about 5 because she became sick and couldn’t take care of herself much less two children. I love my mom though. I lived with my Dad, brother, and Grandma in a small trailer.  When I was about 8 my dad remarried to my step mom. She drives me insane. All she does is complain and judge. My family are hoarders. Because of my OCD it makes me extremely uncomfortable. I was never happy with my life.  Everything crashed this year when my step mom abused me really badly. I went to the police and they filed a report and the DCFS guy talked to my parents. Then he talked to me basically having his side picked already. The only thing he did was make me stay with my big brother for two weeks. During that time I had a church trip that i went to. My best friend in the entire world goes to the same church as me so she went too. This trip was suppose to make me feel better and grow closer to God and my best friend. It did the exact opposite. My best friend and I became not friends anymore. Because of the fact that she dumped me at a time I needed her most, I got an anxiety disorder. I had always had the heart pains that came with the disorder but I never really paid attention to the disorder until the heart pains started happening almost everyday. Ever since this incident everything has been crappy. I feel alone and empty. I feel like I have no purpose on this Earth. I feel like I’m dieing inside slowly. I can’t help but want the pain to end. I think about it almost everyday now. I’ve even written letters to the people who I want to know why I did it, just in case. I don’t know what to do anymore. God is the only one I have now. It may sound like my life seems fine to some people, but to me it’s killing me.