Oversleeping can be stopped by willful awareness. The same way you have an alarm clock is the same way you have to re-train your body. The first thing to do is cut out excess caffeine and alcohol. The next step is to go bed at a sensible hour time (between 10-11:30pm.)
There are many ways to stop oversleeping, some very intuitive like going to bed earlier, as well as counter-intuitive ones - going to bed later each day, for two weeks or so, until you have reached your desired waking hour.
