Teenage girl thinning hair problems!!!!?

i'm 16 years old. my hair is thinning out like no other! i'm using this indian oil to promote hair growth but so far it isn't doing much. i've done some research and found it's possibly i have a problem with my thyroid gland? any help? how do i ask my doctor? what are the treatments? i really need my nice hair back!!! i appreciate all of your replies!