I've been trying to nail down a solid comedown method for coke for a while now, but no luck. (Well, there was this one time I took a whole Xanax bar a half hour after the last line, then I showered, and I was able to fall asleep...but I had to be up for work like three hours later, and that day was brain fog misery!)
I've come to the conclusion that weed only gets my wired at best, lethargic and wide awake at worst. So I usually drink some chamomile tea, take a hot shower, listen to calming music, and lay awake in bed, trying (and usually failing) to count myself to sleep. My roommate, on the other hand, is always able to fall right asleep. I envy her sometimes!