Your friend is very lucky to have you as a friend. Your concern and desire for her well-being are the very essence of what is needed to help someone. I admire your compassion and care.
I would recommend you talk with your high school counselor about services and activities you can do together and things you can recommend to your friend. It is important to remember that your friend needs professional help beyond what you can do. You might go with her to a clinic or to an appointment with the school’s counselor, but your friend sounds like someone who is going to need help from professionals. The guidance counselor is a good place to start.
Sometimes the best we can do to help someone is to let them know we care and that we can be there with them when we can. She is lucky to have you as her friend.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral