I live a messed up life?

I've never been close to my parents. Part of the reason why I'm 15 and have never dated or had a boyfriend before is because I don't want to go through the trouble of telling my parents about it. I don't even know if I really love them. I just feel like I listen to them because I need them; their money, a place to live in. I don't tell my parents anything. My Dad is addicted to gambling, and goes to the casino every week. My Mom has anger management, and yells/hits me and my brother all the time. My brother is only two, so he doesn't know anything yet, but I know he will soon feel the same way as me. My Mom always compares me to other kids, threatens me, and other stuff like that. I'm expected to make straight A's, and anything less would mean I'm a bad kid. We don't get along at all. I know some of it is my fault; I can be a really horrible/selfish person sometimes, but some of it is her fault too, even though she thinks it's all me. Once I didn't finish a project in time, so I skipped school that day to finish it. She allowed me to do it but got realy mad at me (?) She made me lay down on my stomach, and tok a clothes hanger and started hitting me. I had scratches and bruises all over, and she hit me so hard the hanger broke. This morning, I was asleep, and everyone was being really loud, and kept on coming in and asking me questions when I was trying to sleep. I was on my period also, so that just made it worse. She came in and took one of my head bands, and I told her "Mom, if you're gonna take something of mine, you should ask me first." She got all upset about that, and started crying, and saying she hates me, and she'll never forgive. Just because she's okay with me getting taking her stuff without permission, doesn't mean I'm okay with it. She's been glaring at me, screaming, hitting, yelling, calling me all these names for the past few days. It's not just now. I remember when I was 5, I didn't want to eat, so she slapped my face and their was a imprint of her hand on my face. I've been crying and asking God why he put me in this family for the last few days. Help me?