It's just awful when you lie awake like that. I used to have exactly the same problem until I mentioned it to a friend who was a counsellor. She suggested that,after you've wakened and when you start to think about things - worrying situations etc, Picture that situation, imagine it shrinking before you, lift it up, place it in a box, put a lid on the box, then place the box on a high shelf and tell yourself you will deal with it in the morning. Do this with each thought you have, and you will slowly drift of to sleep. It definitely work - I use the technique quite often. Best wishes.