Why cant I sleep!!!!?

ok when i would go to my doctor i would tell her about my sleeping problem and she would just blow it off. so then i tried taking melatonin and that didnt work at all. a couple months ago i went to a different doctor cause i had a jaw problem and turns out to be tmj. so she gave me flexeril to help me sleep at night.. didnt work ofcourse.. then she gave me valium.. didnt work either,, so last night i took an ambien to see if that would work.. and here i am now.. 5:30 a.m. sleep deprived... im 18 if that helps..