seeing as how you want to avoid benzos, z-drugs, and opiates; and the strongest sedative antihistamine(doxylamine) doesn't help, then i'd look into some herbal sedatives. they may or may not put you out, but they're definately worth a shot. the key to an effective herbal remedy is to combine different herbs to acheive a synergistic sedative effect.
here's what i think would work:
first, i want to mention the drug phenibut. it is not a herbal sedative but unlike benzos, z-drugs, barbiturates, alcohol, etc. phenibut acts on the GABA-b part of the GABA complex. it takes a while to fully kick in(can be hours) but when it does it is an effective sedative. it can be found OTC in vitamin shoppes, drugstores, nutritional stores, etc.
second, there herbal sedatives. like i said, the key is to combine them for a stronger effect as these herb's sedative effects are mild. ones to look for include valerian, skullcap, passionflower, kava, hops, and many more. the herbs valerian, skullcap, and kava are weak GABAergics with actions that resemble benzodiazepines but to a much lesser extent.
however combine all the herbs listed above(that are very easy to obtain) in decent amounts and you'll get an effect that resembles that of a low dose of a weaker benzo(once again these herbs are mild sedatives, don't expect valerian or kava to knock you out like whisky & seconal).
*now i saw kratom being mentioned. if you want to avoid opiates, i'd avoid kratom. although no opiates are present in the plant it does affect opioid receptors like an opiate would(not like morphine or oxycodone, but similar to codeine or dihydrocodone). kratom is pretty much vicodin disguised as an exotic plant.
