When you say they are ganging up on you, do you mean that they are physically hurting you, or that they are emotionally distressing you? Either way, if you are underage, you should be able to get some kind of help from your local authorities. If you are having a hard time controlling your emotions, like anger, I think performing revenge magick or such will make things worse for you.
See if you can find an external person who can intervene. In the mean time, there are things you can do so that these people don't have so much of an effect on you. For example, you can create a 'safe place' in your mind where you can go when such things are taking place. You can learn to shield yourself mentally and emotionally so that you are less vulnerable to being hurt. You can ease your stress with physical exercise. You can learn to be assertive in the way that you communicate with these people. And, of course, learning to relax and meditate will always help, although I understand that these might seem difficult at this time.
If they are physically hurting you, I strongly advise that you talk to someone who in your community who has some influence and power. Good luck :)