I think this is a common problem, especially among students
It just needs a bit of planning. When I am doing something exciting I always tell myself I can continue right from the moment I get up, rather than postponing my sleep. I know from experience that putting it off just doesn't work well. It puts me out of sync and I don't feel as good as I could.
Also, it is much harder to push the rhythm to earlier hours than the other way around.