Have you tried or looked into info on Lithium orotate? (This is the mineral form of lithium, not the drug form of lithium carbonate.) Dr. Jonathan Wright has written about it, and here are a few others. There is a lot of info on using lithium orotate, and of course, there is always what people say in the reviews on Amazon with their uses and experiences. Check it out.
myersdetox.com/transcript - lithium - deficiency - mental - health - with - James- Greenblatt (talks about, among other thing, sleep and insomnia and resetting the circadian rhythm.) also drmanso.com/patient-education-guide/lithium/ (Altho he uses the lithium carbonate form in very low doses in water.) Also mindbodygreen.com feeling stressed or depressed/0-11261/ you might be missing this nutrient ( mentions lithium can have an inhibitory action on glutamate.) another one marsvenus.com/p/ar500-lithi... (mentions in the video about sleep and thoughts that won't turn off, etc.)
Thought I would send some info your way and hope it might be helpful for your sleep problems.