It can take some fine-tuning, to find the least effective dose of sleep aids, but that's really what you should try and discover.

In the literature I've read, the natural amount of melatonin released by the pineal gland, to induce the sleep part of the diurnal sleep/wake cycle, is only about 0.4 to 0.5 mg. The thing is, that's very well targeted. Your body knows just where to secrete that melatonin.

Oral dosing is a bit of a crap shoot. If your liver happens to be very active with respect to certain enzymes, a great deal of an oral dose of melatonin would be destroyed before it could even get to your brain. In contrast, another person would see most of an oral dose get past their own liver. You can only experiment.

If you picture the normal curve, the bell curve, that's what the dose/response curve looks like, for melatonin. The peak of that curve, the optimal dose, is different for different people, unfortunately, because of liver activity and other genetic traits. If you keep that picture in mind, you can see that too much melatonin puts you on the declining side of the curve. I know that's counter-intuitive, but that's the way melatonin receptors work. Tweaking is required, but once you figure it out, you can have some assurance that you've learned the optimal dose for your unique metabolism.

Other sleep aids work differently. The valerian dose/response curve is pretty much a straight line, with a positive slope. The more you take, the more effect you'll get. (Within reason.)

Benadryl also has a straight line dose/response curve, but it is very easy to develop tolerance to the drug. It'll just stop working. So, be aware of that, too. If you become tolerant, you just have to stop using it.

There are many prescription meds that target a special histamine receptor in the brain, that in turn induces melatonin release. Some of the tricyclics, for example, ones that used to be thought of as "dirty" drugs. In this case, though, a small amount of those drugs give you just the side effect you're looking for. Doxepin and trimipramine are the ones with the highest H1 receptor affinity.

There are also the benzodiazepine hypnotics, e.g. temazepam, nitrazepam, and flunitrazepam, but there's this unexplainable resistance to prescribing them right now. Benzophobia.

I hope you obtain good results, whatever your options and choices may be. Restorative sleep ought to be a primary focus of your doctor, as he treats your other symptoms. In my opinion, anyway.

Wishing you success,
Lar