It is incredibly hard to get over this alone, so I applaud your move to come here and try to find different ways! I am here for you if you want to talk.
How to deal with your mood is something you will have to learn and figure out. You are still young, and there are loads of people of your age that are struggling to find the right responses to how they feel. A good way to quiz whether something works for you is to try and see the long term effects. Whilst self-harm might relieve the mental pain for the moment, it could leave scars that you have to carry with you for the rest of your life. Same with drugs, it is a short term solution. It might take the edge off the real inner hurt, but it won't make you feel better after the effects wear out.
It is best if you start looking for a cure rather than a short term fix, and that is very hard to do on your own. Since you have so much problems with your parents, I advice trying to find a third party, like a school counsellor as Awty advices. You can visit your General Practitioner as well. I used to think I could fix my problems alone, and I couldn't be more wrong. Even if you can do it on your own, others might catalyse your progress, so it is always worth it.
For now, just talk. Perhaps you have friends you can talk to? When I was your age some years ago, I wouldn't talk cause I thought it would make me look weak or anything. Truth is, it takes guts to talk.
Like I said before, I am here for you if you want to talk
. For your information, I am 20 atm, so it wasn't too long ago that I was your age.
Take care, and all the very best!