I have insomnia too, Chronic Insomnia (which has nothing to do with how little sleep I get and everything to do with how long I have gotten very little sleep) and I eventually found a doctor that had me do tests on my blood chemistry and neurotransmitter levels.
It turns out I basically produce twice as much cortisol (the long-term stress hormone that tells your body “fight or flight!”) as any normal person does, and thats why I can’t fall asleep until 2 am. Hes put me on a regimen of supplements that are regulating my cortisol levels, and let me tell you: 7-8 hours of sleep feels amazing! Essentially, if you’ve been suffering from insomnia for longer than three months, its not actually the problem (though it sure feels like it) but a symptom of something else going wrong in your body. Try and find a doctor willing to work with you to find a solution! I found a chiropractor who specializes in neurochemistry, but I think hes one of a kind