I'm not sure it's as much an issue of too much sleep but rather, maintaining a set schedule. Try to go to bed and get up at the same times each day. On those days I am up late, I've found I still have to rise at the normal time (0430 hrs). Otherwise, I get up with a headache that persists, it seems, into the early afternoon. I've found it better to occasionally sacrifice a few hours of sleep to avoid the headache! My normal practice is to attempt to get five to six hours of sleep, daily.