I think the best thing for you to do would be to consult your school counselors. They have most likely dealt with many students in the same position as you, or at least similar. You can get a ton of opinions on here, but you don't know a single person here and they don't know you. All you're getting are words.
After that, you need to sit down and hash out what's gonna happen if you walk away from this. And it's okay to walk away. But you need to have a plan, an idea, a desire, something that you can work towards once you're not in school anymore.
That's my advice: talk to someone who specializes in dealing with students who have this desire and then sit down and be real with yourself and work out a plan for the future.
Best of luck to you!