Sleeping WAY too much?

This past week, I have been sleeping not only very deeply (through 4 seperate alarms on 2 seperate alarm clocks), but for much, much longer than is usual... beginning with 13 hours on Sunday and fluctuating to 14 hours the night before last, and 11 hours last night. I'm not groggy at all from oversleeping. Cl didn't finish until this past Thursday, when I was already sleeping too much. What is gong on?