Smoking cannabis significantly raises your melatonin levels, 5,000% on average for someone with a low tolerance. It's what causes the "burnout" and chilled out feeling during the high. Melatonin is a hormone your brain naturally creates to tell your brain it's sleepy time. So when you smoke weed and it gives you the melatonin blast, your body stop producing it itself because the weed is doing the job for it; hence, when you quit you have no source and can't fall asleep. Staying abstinent for a few more days, probably a week max, will get your body producing the melatonin itself again, so no worries:thumbsup: