Hormones are certainly wacky, seedless. I experienced something similar when my wife was taking a certain brand of birth control pills a few years back. It was *awful*. It wasn't depression in her case, it was hormonal, because once she talked with the doc and they changed her prescription, her sex drive magically reappeared, stronger than it had ever been before. I had trouble keeping up!
But during those 40 years in the desert, it was a real dark place in our relationship and I almost did *very bad things* during it. The thought of having an affair or hiring an escort became so strong, I hated myself and felt so helpless and frustrated that I was the one suffering depression! Glad that's over. I'm pretty much manic all the time now...just call me unipolar! (I'm not poking fun at bipolarity, please believe that; humor=defense mechanism).
Hormone therapy is such a tough call, though, due in no small part to what you've already been told here. While I can't advise you what to do one-two-three (*POOF* - DONE!), obviously something must be done. This won't just magically go away like I used to wish it would.
The things you cite, sleeping all the time and lack of sex drive, unfortunately do sound like depression. What worked for me was drug-free, I never took antidepressants; it was the company of really good friends combined with activities that gave me a sense of accomplishment and self-worth.
I had to force myself to do them sometimes, but ultimately being productive and getting lots of positive reinforcement really shook those blues away.
Does your wife have any activities that she enjoys or used to enjoy that she's given up on? Maybe you could buy her something for Christmas to help her get motivated again and interested in things and enjoying herself.
Any authors she enjoys? Movies? Stocking stuffers. Any hobbies that could take her mind off things, building ships in a bottle, cross-stitching, exercise? How about a trip to the craft store, or a membership to a gym, and you go with her?
Challenge each other, have fun together, go out of your way to make her feel special -- that's the main one, and get her re-involved in the process of being joyfully ALIVE!!
Even if she's not depressed, the things I just mentioned certainly can't HURT. What you CAN'T DO, under any circumstances, no matter what, is make her feel bad about you just told us. DON'T DO IT!! I gave my wife a hard time about the sex drive issue, and it made her feel awful; it's the closest we ever came to breaking up and man, lemme tell ya, there's just no good that can come out of that kind of confrontation.
So you must come at it indirectly, and be persistent! You will both reap the rewards.
I know it's hard when you feel left out and unappreciated to really lay it on thick: flowers, compliments, love letters, and no pressure at all to have sex -- but that's my advice, and I'm sticking to it.

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