Battling insomnia since 4 years ,even after stopping medication for four years

I have had insomnia for 4 years now ,I have stopped every medication that led me to insomnia (nitrazepam and amitritilline )I battles zero sleep for months ,then gradually managing from 1 hour and now I can sleep for 5 hours only.what could be the problem that’s still making me experience this ,my brain feels and stay awake at 3am