A horrible thing happened, you have every right to grieve and be afraid before you goto bed, cry it all out whenever you feel like it, she was probably a big loss to you.
The first way to feel any better if acceptance and getting over denial, then you can move on with coping. Try to understand that what has happened has happened and nothing can change that, no one can bring her back, but life moves on no matter how slowly. It's good that you understand how suicide isn't the right answer, and how it hurts everyone involved alot, it's sad your friend didn't know. Next time you goto bed, close your eyes and picture her as much as you like, picture her in the moments you had together, the seconds you cherished. She might be gone but it doesn't mean you have to be afraid of remembering her, let thought run through your head, no matter what thought it is if you try to block it it will just come back sometime.
I think a talk with a psychatrist or a psychologist would be a good idea for you, they can be really helpful most of the time, cutting is a bad habit you might want to try and lose.
If anyone wants immediate advice don\'t hestitate to contact to me on AIM (AOL instant messenger) - aim: vodkasmodka
Eccentric! Not egocentric!