Hey! I used to have a chronic sleeping problems, getting into bed and just not feeling tired.
Seeing a dietician might help, they can sometimes identify foods that are causing problems.
Another thing as you mentioned is the stuff outside of diet, and those things are less easy to control. A lot of people find meditation useful, or yoga.
To be completely honest, a really big spliff usually does the trick!
Do you work in an office or at home? Another big factor is lack of exercise, you might hit the gym once each day but perhaps you need to be even more active yet? Currently I'm doing a fair amount of exercise each day, my sleeping patterns are really fine, but when I'm working full time in an office, my sleep is shiiiitty!