My only experience with this was the first few nights after sobering up in which case tylenol pm helped me a great deal, although I can't stand the idea of any kind of medicine even when in need of it (and not sure why), but, as Astro suggested maybe it's something you could talk with your Physician about? It maybe an underlying problem causing the insomnia that you're not aware of. It wouldn't hurt to ask your physician some questions and figure out where to go from there. I'm sorry I couldn't be of more help. If there's something I may be able to do please feel free to PM me.
Wes