I have this problem, but I know what causes it:
Disturbances in my pattern, usually terms ending will knock my body off it's perch
It happened recently, and I was sitting there until 4:30 one night and had to find some way to stop it...
My folks' alarm went off at that point, it normally goes off at 5:30 but they haven't yet changed it to account for daylight saving (or whatever it is)
Have found two mini-cures for this though:
1) Read a book that you've already read before. I've read a series of Tom Clancy books (Net Force if ur interested) about 4 times now, and have started again. Using this method I have got the time back to 1:30 recently.
2) This is a last ditch method that I used a while back when the times I got to sleep got up to the 4:30 mark or so... Don't go to sleep... The idea is to stay awake that night and the rest of the day until an hour or two before you want to go to bed (be careful of that, you'll want to go to bed all day
) and then go to bed as normal.
You will go off like a light, guarenteed
, and sleeping pattern should resume to within a few hours of when you went to sleep,
If that doesn't work, try it again