You said that you have a friend that you can talk to. IMO confiding in an older friend brings me relief; I feel like the weight of the problem has been lifted and that my 'older' friends can help and guide me. That is one thing I have always regretted from when I was a teenager:- that I never told anyone how I was feeling. I believe that if I had then things may not have gotten as out-of-hand as they did, and I could've started working on my issues a lot earlier...
Best of luck in whatever you do; you say you are looking for help, and you are reaching out, so take that step and trust your friend...Even if she does tell your parents at least it is out in the open and you can move forward...