@Browneyes4,
The good news is that you only have to survive a year. Once you turn 18, you are legally an adult. Can you lay low for another year?
That being said, it sounds like you were raised in a difficult situation. You should try to find resources to help you to be happy and healthy as you change into adulthood. This is something that you might be able to do now. You don't want to do something that will make you unsafe or unhappy.
Do you have counseling resources available at school? A counselor may be able to point you to places that you can get help. Many of us have found that talk therapy helps a lot to get help through difficult family situations (and it sounds like this may apply to you)... a big part of it is learning how to be happy once you get out of an unhappy environment.
Again, I don't think you need to worry about foster care, unless you want to... it may seem like a lot, but a single year is not that much time out of your life. You can make it.
I do hope that you can get help, and that you can get yourself into a good place where you have the resources to start your adult life. The key is to learn to be healthy and to take care of yourself.
My advice is to find yourself some good counseling resources, either through school or through an social service agency. Your doctor may also be able to help.