Insomnia and parasomnia patient here, sometimes I don't sleep for a week. First thing you should do is visit a doc, get into a sleep laboratory. They might even scan your brain. If it's not the result of a bodily illness they will tell you about sleep habbits and meditation and garbage - ignore that. All of those retard advices will not work.
All you can really do is drugs. I prefer benzos because they're the only thing that even lets me feel tired, have little side effects and the sleep they induce feels very cozy and good compared to antihistamines like diphenhydramin or promethazine. Often enough you can get back into a good sleep cycle with benzos and then leave them be for a while. They are very very addicting.
If you can't find a good doc for a perscription because these fags will rather tell you about hot tea and sound therapy you can always buy the shit you really need to sleep on alternative market places.