sorry to hear your feeling so low but so glad you come on here looking for help
seriously well done, i know that the hardest thing to do is take that 1st step and acknowledge that you need help.
i know how addictive the feeling can be. best advice i can give you is keep your injuries clean and when you feel the urge try and divert your mind, call a friend, watch your fave telly programme, munch some feel good film, listen to music... anything! if you still wanna hurt yourself there are things you can do instead, crushing ice in your hand, punching a pillow or even drawing on your arms with a red pen can help.
really though you need to find someone to talk to, anyone you trust.
good luck hun and keep us posted