I have always been a night owl, never a morning person, so waking up was always sort of an issue for me, but it wasn't until my early teens that it started getting worse.

Now as an adult mornings are the worst time for me, I can hardly get out of bed, and never really want to.
There is no reason for it in my head, except on some days when I have to act like I actually care about things so people around me won't get worried.