Just a nature. Your body and mind will do this every so often, you can try warm showers and then right to bed, calming sleep teas, glass of warm milk, making sure that the room you sleep in is complete dark, and temp is lower than usual. Also dont read watch tv in bed only for sleep, your mind will keep thinking if you are in bed while watching tv and reading then all of sudden try to sleep, after all that, try some 5 htp to come down from stress. maybe you need to jerk it before going to bed that helps sometimes