How do i get rid of an obsessive ex girlfriend ?

i'm 16, i dated a girl starting in grade 9 for about 9 months. i broke up with her 7 months ago and she wont leave me alone, she cuts herself (shes showed me) she threatens to kill herself, and she hares me. i've talked to my parents, i've talked to her parents and i've talked to the school. its hard to avoid her at school because i have a small school and shes in one of my cles. shes attacked me on many occasions in front of people including teachers. she's got in trouble but she wont leave me alone. i've tried everything to get her away from me but nothing works. i've talked about a restraining order to my parents but first of all that's embarring to me, and secondly she's obviously not mentally okay and a restraining order wont stop anything. she's been getting "help" from school councillors but it do sent seem to be helping at all. i've run out of options. she stresses me out more than anything because she wont let me live my high school life that i want to live. any suggestions for what to do would be greatly appreciated. thanks.