I hears Benedryl works good in combination with melatonin. I've never tried Benedryl though, as they don;t sell it here.
I do use melatonin as I have quite bad insomnia as well. When I am really bordering insanity I take a Zolpidem, but I try to avoid that as much as I can, for me this works wonders and knocks me out cold, which is exactly what I need at such times.
When it is less bad I can make due with Melatonin, Gaba seroquel and Trazodone ( last 2 prescribed by my doctor)
I hears that L- Tryptophan also works good with Melatonin, and its available OTC,