Before I say anything, I want you to know that I've been in a situation where I felt the same way. But you CAN still have the life you want to.
Always remember that your life is exactly that - yours. Not anyone else's. Don't let anyone keep you from fulfilling the dream of what you want your life to be.
Near the end of high school, I made the decision to leave home, and later started my own company and have spent every day working towards the ultimate dream I have for my life. I also recently was able to move to the other side of the country since I've always wanted to live somewhere warm. Though it's often challenging, I can say that even at the hardest moments, it's still worth it. If you are in an unhealthy environment with your family, you may need to do the same and just separate yourself from them. If you're not able to get away on your own, find someone safe to stay with - perhaps a friend or someone who is able to reach out and help you in your situation (e.g. someone at your church, a teacher/professor, etc).
Also, I would highly encourage you to read the book "Safe People." Here's an amazon link for it: http://www.amazon.com/Safe-People-Relationships-Av...
That book has helped me a great deal in learning what qualities to look for in people who genuinely have your best interest at heart. No matter what happens, know that I'm thinking about you and wishing you the best.