I found it difficult to sleep when I quit smoking as so many others do, so, I'm going to give you a way to get around mind clutter that may help.
To me mind clutter is when you are thinking the same thoughts over and over because you don't want to forget them in the morning.
My solution was to get up and write out everything that was on my mind.
It may take 5 minutes or 30 minutes but what it does is remove those thoughts that are keeping you awake and allows you to give yourself permission to sleep and address them in the morning.
Simple Solutions Work Best