Help me please my lifes in a mess!?

At school a group of people are bullying me, I just ignore it and get my own back because I believe in 'an eye for an eye' from the Bible. When I get my own back they run up to teachers saying what I've done then the teachers are against me and my 'friends' join in with the people bullying me. I do my best to be nice to people but I just see myself offending people without meaning to!