You're not a freak. Just think of it this way... Whatever idea pops into your head, somebody has already been there and overcome it. So you are never alone.
Just stop and think before you self harm. Keep a journal and a pencil near by.

Ask yourself why you are doing it?
Why emotion are you feeling?
And if you do it, how do you feel afterwards?

It's really helpful. It's just a little exercise at first. But hopefully in time you will just journal instead if SI.

Best wishes. Stay strong.