How well do you think this will turn out?

This has been the hardest two years of my life.. I have been diagnosed with bipolar disorder and self mutilation.. I also secretly suffer from bulimia and anorexia. I am 13 and 14 in about two weeks, I have always had a lot of friends and then this school year my anxiety took a toll on me I missed over 50 days of school due to it and refused to go anymore, I have been in the partial hospital program for a week now and have not been at school in a month. School is over on Monday and me and my friends don't dislike each other or anything but we are slowly starting to drift apart and I barely talk to anybody anymore. I am going to go to a therapeutic boarding school soon for around 10 months, so that will take up another full school year and my eighth grade year, also hopefully sorting out my issues and getting my life together. I will come back and won't have any friends and will probably start a new school with no support from old friends. I am so afraid that I will never have friends again.. My old friends know my problems right before I leave should I contact them and ask them to write to me to support me through recovery? I am so stuck...