I can't believe I'm writing this, but .... Force yourself to get up early one day when you don't have anything important to do. You'll be deadtired all day! Then go to bed earlier that same evening - and do it again the next day! It may take 2- 3 days to turn you scedule around, but it CAN be done!

If you have the energy, then it's also a good idea to take a long walk, or do something exhausting - like garden work.