Hugs Sue. I quite often have that trouble too. Its so frustrating!! I'm not saying this is what you have but for me I know when I am not doing so well with my anxiety sleep is one of the first signs. Sleep issues can be a symptom/sign of depression and anxiety so if you are experiencing anxiety too its probably a good idea to see your doc and have a chat.
Maybe a trip to a naturopath or homeopath for some sleep remedies. I use a great sleep spray from the body shop that works all night. I find it makes a difference to my sleep.

good luck!!