One thing I've noticed about my headaches, just before they go away I'll feel sleepy. But only for about 15 minutes, then the headache is gone. Forcing myself to sleep doesn't work, I have to wait for that sleepiness to come on by itself. When it does I pretty much know the headache is almost through.

Green is indeed the basic color of healing. I see it a lot. It can also be the color of a new growth period.