Hi, Lissa,
I'm really glad you are here and posted about what's going on with you. Sounds like so much that I would be screaming at people, too.
I'm a bit puzzled by something. If you are 18, why aren't you able to get state assistance on your own? I don't know where you live but it would seem to me that you might qualify for your own assistance independent of your parents? You might check into it.
We are always here for you to talk to. There are many, many terrific people here who will listen to you and who have been where you are and can understand the frustrations you go through.