As a professional insomniac, you have my sympathy.
No matter what time I go to bed, I always wake between 4.40 and 4.45am.
When I go to bed I don't so much drop off to sleep as fall into a coma, but no matter how tired I am I still wake at the same time. Once I am awake, I have to get up.
Sometimes I come downstairs, have a milky drink and then go back to bed and read quietly. After 30 minutes if I haven't gone back to sleep (most days) I get up and stay up.
I have even taken a sleeping pill at 4.30am. This made me sleep soundly for all of 30 minutes and I felt foggy brained all day.
I have learned to live with it (I had all the ironing done by 5.30 this morning!)