If its about an actual, medicinal, more or less sustainable treatment of insomnia, I would suggest a combination of mild OTC meds, supplements, and maybe a low dose of non-recreational prescription pharms, with benzos or z-drugs reserved for days when your normal cocktail of supplements or meds isn't enough (however, even then one should keep the dose to a minimum).
A good combination could contain something along the lines of:
* A sedating antihistamine (like diphenhydramine); if it's sorrows and gloomy thoughts that are keeping you up at night, you might want to see a doc about an antidepressant that combines mild sedation with serotonin reuptake inhibition (trazodone being a good example)
* L-theanine. Not all that much into supplements, but l-theanine works, and is non-recreational.
* melatonin. See above.
And, as an emergency medication, maybe zolpidem (although a longer-acting drug may be preferable if your problem is less about falling asleep than repeatedly waking up at night).
Benzos and Z-drugs (zolpidem, zopiclone, zaleplon) can be effective in the short term, but tolerance builds rapidly and addiction is a distinct possibility, to say the least.
If you suspect your insomnia to be related to a mental health issue, I would strongly suggest you talk to a doctor about it. Trazodone or the tricyclic antidepressants, for example, can help you fall asleep at night, and possibly reduce the anxiety that caused your insomnia in the first place.