Question: It is quite hard to turn back the cycle to normal, but far from impossible. When I usually discover my sleep cycle has shifted, I stay up as long as I can and plan as much as I can ahead for the next day, then I hit the bed.
I set my clock to wake me up, when it is supposed to, so that basically I have some time to wake up and refresh myself with a shower maybe.Now you might think the waking up part is hard, but wait until you have to face the next time you have to go to sleep, to get the right 7-8 hours of it.Follow the planned out day and no matter what, do not get frustrated if you do make mistakes. And you also train your willpower like that :), which makes it easier following a normal cycle more often and keeping you on the track.