Dad's or Mom's

I have been living with my mom for 16 years. I didn't really fit in at my public high school and I have always gone to private school and also, I think my mom and I were too dependent on each other and she can be very irrational. I have had an iffy relationship with my dad and my parents don't get along. My dad is remarried about 10 years ago. My stepmom and I don't get along because we have very strong, yet conflicting personalities. When I moved to my dad's, which is about an hour and a half from my mom's, everything was great, but then I started to have problems with my stepmom and she would yell at me about how terrible I am etc. I don't really think it is her job to discipline me, but I also don't see myself as a terrible person. I am an honors student and I have friends and I really think I'm a considerate person. Anyways, I go to a private school near my dads house and for the first time, I really love going to school everyday. I am on the swim team and I love my friends and classes. However, things with my stepmom escalated and now she says that I am a danger to her (and my dad's) six year old son (my brother) so I cannot be in their house anymore. The police came and my dad said that he didn't want me in the house either so I couldn't go in the house. They are being so extreme! He says he will withdraw me from my school in the middle of my junior year (beginning of january) and I have to go to the public high school near him and live in an apartment with him because I can't be in the house with my stepmom and brother. I'm not on drugs, I don't do anything illegal and I'm not malicious or dangerous. Moving to a new school or back to my mom's house especially in the middle of the year will be so bad for me and as much as I don't like living with my stepmom, I really want to stay with my dad and brother and convince him to let me stay at the school I love. I talked to the director and she said that I should keep up with my homework because there is still a place for me and I am still enrolled in my classes. I don't want to go back to my mom's because my great-grandma is there in our small apartment and she is in hospice care. My mom is really irrational and I love her so much, but she can be really difficult to live with. I don't want to go back there. It has been so good for us not to be in such proximity to each other. Please help me... I don't know what to do.

The pros and cons seem pretty self-explanatory.