What disorder do I have, if any?

There are more teenagers out there like yourself, than you believe. The cutting/scratching you describe is OCD (Obsessive Compulsive Disorder)-- the person with this is obsessed with and, feels compelled to cut/scratch themselves; this is done as a release to supposedly feel better. And you already know that you suffer with periodic depression. The good news is that they have lots and lots of different medications to help both problems, it's just a matter of finding what works best for you. It is, therefore, extremely important that you seek professional help through mental health services in your area. You should ask your parents to help you in this, and hopefully they will. If they do not, I suggest you talk to your school counselor, and seek their help in doing this. You can get the number of the mental health clinic in your area, and try to arrange an appointment for yourself-- I don't know how much luck you'll have with this, but it's worth a try-- and if you have health coverage you should be okay (I think all school age kids have some type of coverage). You could also call the suicide hotline, speak to whomever answers, tell them your problem, and ask if they can help you in any way to get hooked up with a therapist. Again, there are a great many young people your age that have similar (or worse) mental health issues-- it is nothing to be ashamed of. If you do this, get the professional help you need, your life will be immensely better. I hope you will do so, and I wish you the best of luck.