Would this be considered child abuse (and would it be wrong if I didn't like him)?

I am 13 years old. Now, I don't want answers pertaining to my age and such. My parents divorced about 4 years ago. My dad and I used to fight a lot. Recently, he got a girlfriend. His girlfriend has two kids. One is in 8th grade and one is in high school. He used to hit us, little things like pulling ears and pushing lightly. One Halloween before my parents divorced, he pushed me down to the ground. Yes, I was crying. Before that, he also dragged me up the stairs and bruised my leg in the process. This happened either because I was being "disrespectful" which I wasn't, or was fighting with my brothers. He yells at me a lot still. About 3 months ago, he took me to an abandoned football field, and pushed me into a pole. He also hit my head into a pole on a chain-link fence. I had a bump on my head and a headache for 2 hours. This happened because he told me not to talk, and I didn't. This made him angry, and he made a detour on the way to his house to the field. Looking back, it was a bad choice. I was taken to a counselor by my mom because we had family problems. I told the counselor with my brother. In the next week, two officers went to my brother's school.They asked questions. They didn't go to my school or my brothers. They showed up at the house about 1 hour after I got back from school. The asked questions and left. My dad found out, and wasn't happy. He didn't hit, just yell. He had his fiance and her kids to lie about how he is so nice to us. I don't get along with the fiance at all.The police didn't do anything, I don't know why. Our soon-to-be stepsister dislikes us because we don't know what "child abuse" is.She says we don't know how "easy" we have it. There whole family says that it isn't abuse. I am confused. He put my two brothers and I in a room that is smaller than the stepsister's room. We are cramped. I can't sleep. I dread going to his house. Please answer!