Need advice to sleep?

I am at the end of my school holidays. Admittedly i have been sleeping in for most of it, but i have tried to correct my sleeping pattern in time for school. Now, after a week of trying, I find it very very difficult to rouse myself out of bed in the morning, and then I am tired all day until about 9 pm when I 'wake up' so when I go to bed at about 11 I lay awake for 1-2 hours before finally falling asleep. I want to correct my sleeping patterns so I am not tired all day (usually with a headache as well) as this is my final year of High School. Any advice is helpful, thanks