Self harm

I first cut myself when I was in 8th grade, it was a method to release stress and cope with my depression. I have been molested by 4 different individuals in my life, all at different times in my life and over several days. In 9th grade I forgot about it all and was fine until now. I'm now in 11th grade and I have started to cut again.

It started when my boyfriend lied and went to a party without telling me, I know it sounds ridiculous but I couldn't help but to think about all the abuse I've gone through. I don't know how to stop and I'm afraid it will get worse if I can't get my head off of it. I've also lost 10 lbs in the past week from being so stressed. I now weigh 99lbs and I'm scared. Advice please??