How Can A Rare Bone Disease Causing Density Issues Be Treated?

k umm i am fourteen and have a rare bone disease but dont know what it is yet. my last doctor has given up. to give you an idea of how fast it progresses first time i went to this doc. i was -4.1 bone density second time after being on treatment 6 months later was -4.7 that was over eight months ago . i brake 2 to 3 times a year for the last 3 years. have not broken so far this year cus no longer doing gym and being very careful. i can go to shriners in may or give up. i know i do not have osteogenesis imperfecta, vitamin d is ok too should i go to shriner, what could it be, what do you think it is, what should i do, and how bad is this is it really serious. like i dont know how bad -4.7 is on a childrens scale please help me i am kinda scared