Dark times -- literally! Like... It's dark!
Here is a note I wrote to a friend, and I hope they won't take it amiss if I republish it, slightly revised, on behalf of anyone else who is suffering in this season:
This sounds like Seasonal Affective Depression [SAD] to me (although as you point out, there are plenty of situational reasons to be depressed)*. It is, after all, the equinox and the light has changed!
I know what SAD is, and the best (and indeed the correct) way to think about it is as a disease for which there is treatment. I have been there.
1. No matter what, FORCE YOURSELF into some sort of motion every day. Even if it is only to get out of bed and get a book or walk to the window and look out. If you don't want to shower or brush your teeth or whatever, don't worry about that, you can do it when you are well, just force yourself into SOME KIND of motion, no matter what. Then do it again.
2. GET PLENTY OF LIGHT. This is the key.
a) Try walking
b) If you sit, sit where there is light, say, at the window, or even possibly outside at a cafe (see #1).
c) get yourself a Verilux Lamp:
Order it from Amazon, you don't have to leave the house ;-)
Don't just order a lightbulb, treat yourself to a nice lamp. I did, the first year I was here -- Maine is very dark! -- and it's one of the best things I ever did.
3. Some recommend lots of vitamin D. I have never tried that, but you might find it useful.
4. UNDERSTAND THE DISEASE. SAD in particular (although depression in general) is very insidious. I remember when I lived in Boston and I was travellng over the Charles on the Red Line at 4:30PM in the frigging dark because of turning the clock back. And I was reading a Scientific American article about SAD, which mentioned one of the symptoms: Craving for starch. And I realized... I was eating, like, an entire bag of cookies at one go, and in fact I felt tired, sad.... ZOMG!!!! I've got SAD!!!!!! The kicker here is that I already knew what SAD was, I knew I was susceptible to it, I knew I'd already had it, and I knew it had caused big problems for me in college (because the light changes at key points in the academic calendar).
So, I "knew" I'd had SAD and could have it again but I didn't realize I had it, until I read the article! That is how insidious depression is.
I won't say "Cheer up!" because that's like telling somebody with a broken leg to start sprinting. However, I do beg you to believe that SAD is a disease and like any disease it is treatable and remediable (And AKAIK it is also the empathetic and imaginative who are subject to it. No such thing as a depressed sociopath -- they are big on smiling!)
Do take care.