It is never, ever your fault. Step back and assess the whole situation and try to find out why it is going on. Fine someone you can really trust and tell them everything. Don't hold any details back. Remember this is your life and you don't have to suffer for anyone.
Life is too short.
If you don't stand up for yourself you will regret it later in life and it will affect you. It will stop. Have faith and courage in yourself and it will get you through. If you agree with them, they lose their point. Nowadays I have realised that I am a good person, with a lot of good to do in the world - just remember that to create and bring happiness to others brings happiness to yourself.