To add another anecdote, I usually do not have trouble sleeping through the night. Once I lay down, it takes awhile for me to fall asleep, but once I do, I sleep 8-9 hours without waking up. However, even when I awake, I still feel drowsy and not "rested".

Very recently, I started taking 3-6 mg of melatonin about thirty minutes before going to bed. I find that I fall asleep more more quickly, but I inevitably awake roughly four to five hours later, completely lucid. After a few minutes of being awake, I roll over and easily fall asleep again for another three to four hours. When the morning comes, I wake up feeling much more refreshed than I did when I slept continuously throughout the night.

I usually spend long nights in front of my computer, and from what I have read, melatonin production is reduced by the presence of blue light. I have started using Flux in addition to my melatonin intake. I can only guess that I am starting to enter a more "normal" sleep cycle.