I learned years ago that any chemical that helps you sleep ensures that you can't sleep without it. I've used everything from thc to Benadryl to lavender and everything in between.
It all had the same effects: slowly degrading effectiveness and sleeplessness without it.
Pro-tip: find the source of your insomnia. Is it chemical or is it electrical or is it just habit? Doing a real sleep test and working with doctors was life changing. Mine was habit and anxiety. Meditation and therapy have helped.
Anecdotal, I know. But what happens when the thc runs out? You crash. That's what I did.