Part of the circadian rhythm is a temperature component. Your body temperature should go up during the day and then cool down as it gets close to bedtime. If your body temperature doesn't go up high enough, it will interfere with the signal to go to sleep. A hot bath can help. It is more relaxing than a shower. It raises your body temperature and when you get out your temperature starts to go back down.

Also, the more dark the room where you sleep the better. Light on any part of your body interferes with melatonin.