I have delayed phase sleep disorder... I find it hard to get to sleep before around 3 or 4am every night.
I think I have a similar problem except that I'm not quite that late. I usually don't want to go to sleep until 12.30 am. I fall asleep pretty quickly, but then I don't want to wake up. There are some mornings where I hit the snooze button on my alarm five or six times. If I'm working or have to be somewhere, I drag myself out of bed but end up arriving half dead. Unfortunately, I just cannot function on four or five hours' sleep a night - I tend to need to sleep at least nine hours to stay sane. I don't know if there's a solution to that, other than to change the world so that it suits night owls rather than morning people.