School is out now, but when school is back in could you talk to a school counselor?

Nammu is correct, BPD and other personality disorders aren't supposed to be diagnosed before the age of 18. The last therapist I saw for any length of time was when I was 17 and she thought I had it, but didn't officially diagnose it because I was only 17 at the time. (In my adult years I did research and diagnosed myself with it because I'm basically textbook BPD.) She did give me some worksheets to use because she was certain I at least had some traits of it and that the worksheets would help.

Since you are self-aware (super important for dealing with BPD btw) and are willing to take some initiative on this, perhaps another option for you would be self-help methods like looking up Youtube videos, books, or articles online that can teach you techniques in dealing with this. I've had much better luck helping myself than using what few things I got from therapy, and the more aware you are of yourself the better luck you may have in doing the same. Still, when you can it would be a good idea to get into therapy.