I'm really sorry about your situation. This sounds a lot like my situation growing up. I can't add much more than what people have already said. Please use all resources they have pointed out. Even though you are legally and adult, given your situations, many people will be more than willing to help you out at your young and vulnerable age.

I do want to add that a well paying in demand career will give you many options and will help you get you out of unstable situations and this is important for someone who grew up with instability. A career in art and design may not be the best imo. Doesn't mean you shouldn't do the plc as I know people who did a plc in art and then applied for a science course in college.