This sounds terrible. You seem to be surrounded by toxic people who hurt you and use you. Sadly, not everyone gets the family they deserve. Also sadly, a person who is used to being put down often finds “friends” who continue the negativity. One of my teachers used to caution us never to underestimate the pull of the familiar.
The good news is that you are 17. You’ve written a thoughtful and reflective letter. That shows me that you have it in you to discontinue the trajectory of life you’ve been on. You can make new choices.
I suggest you start separating from this friend group and make yourself available to people who will give as well as take, who will see you for the interesting person you are and who will be there for you.
The best way to do this is to identify an activity that truly interests you and get involved. Like attracts like. People who like the same things are often interested in knowing each other. Don’t be concerned, at first, with making friends. Just throw yourself into the activity or cause and be your best self. Friendships will naturally evolve.
Meanwhile, spend less time at home. Go to a library or stay after school during the afternoons. Work hard on your grades. Talk to your school counselor about whether you qualify for a scholarship to college. Round out your resume by doing some volunteer work or getting a part time job for work experience.
In another year, you could go off to school and make a new start. If you aren’t interested in more school, start looking for job or volunteer opportunities that will take you out of your town and into new experiences with new people.
I wish you well.