I should add here that, if you have a system that works for you, that's great! Not trying to disrupt anyone else's treatment if it's working for them. I'm not a doctor, and everyone's body is different. Melatonin can be a useful sleep aid for *some* people, when timed right, and when taken in reasonable amounts (ie single digits, not 10mg+!). It's just most effective as a tool for managing your sleep schedule.
When my CFS first hit, I first went to see a sleep doctor. They discovered I had multiple sleep disorders, which I had probably had my entire life. But since I was seeing sleep doctors, all my CFS symptoms got blamed on sleep problems. I spent about 5 years with a lot of different sleep doctors, reading all kinds of white papers on sleep medicine, even reading sleep medicine textbooks, before I finally figured out I had CFS.
(You would think that, over the course of that five years, one of these sleep doctors would at least *mention* the possibility of CFS, right? Certain CFS symptoms overlap so closely with disorders like narcolepsy and idiopathic hypersomnia, you'd think they'd be familiar with it. But no, like many of us, I had to figure it out myself.)
In any case, I do know at least a few things about sleep. Melatonin is not regulated by the FDA, and drug stores sell it in huge doses, so there's this widespread public misunderstanding about how the supplement works. People (understandably!) think it's a safe, natural sleep aid, but it's just a bit more complicated than that. Studies on the use of melatonin as a treatment for insomnia have been mixed. It does have a mild hypnotic effect on some people, but you have to be really careful about the timing, or you can mess with your circadian rhythm.
There are also other potential side effects, like night terrors, but for most people, it should be relatively safe and not habit forming. There are no known long-term negative effects. If you're going to use it as a treatment for insomnia, 3mg is probably a good dose, and it's probably best not to go much over 5mg. Here's a bit more info:
It's also important to know that the actual contents of melatonin supplements vary widely by brand. Many doses are totally different than what's on the label, and some contain totally unrelated ingredients, like serotonin. That can be true of any supplement, but it's especially true of melatonin. You likely know all of this already. There are sites that test the purity of supplement brands, and I think brands like Jarrows or Nature's Bounty tend to be trustworthy.
Anyhow, I use melatonin to help maintain my sleep cycle, but I use 1mg of Ativan to help me actually fall asleep. And I use Baclofen and LDN to help maintain the quality of my sleep. I take Gabapentin at bedtime too, but that's mainly just to relieve my muscle soreness.