I know what You mean..
Try this:
1: Set it straight over a period of a week or two, simply cut back 30-60 minutes on the bedtime Your'e used to, every day.
2: For more effect; avoid sugared things (soda, and Coca Cola especially), coffee and tea, at least for the last 4-5 hours before bedtime.
It's always worked great for me in such situations
