I agree with the others. Sleeping that much is a definite sign of depression. I have seen this symptom in at least three people I know who were later diagnosed. The good news is if she is depressed and gets treatment her mood should definitely improve. The bad news is some anti-depressants affect sex drive. Wellbutrin seems to be the best.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver