I take antidepressant medication and have continually for years. I still look at the things you mentioned, too, though. If my mood gets consistently low and stays there, I may suspect that I need a medication change, but if it's and up-and-down kind of thing, I often find that it's caused by poor sleep, what I'm eating, anxiety about life events, seasonal changes (I had a tough month when the days started getting shorter back in the early fall) or something else identifiable.

I still seem to have a moderately bad case of depression even when I'm taking antidepressants. I have a couple of autoimmune conditions, which often come with depression, so I suppose I've accepted that "fairly stable" is about the best medication is going to do for me. The rest I have to achieve through controlling my environment, as you put it, plus working in psychotherapy on how I approach the difficulties in my life.

I think there's a "holiday funk" going on right now. I have been taken aback several times this week by the really foul moods of people that I've had minor encounters with (people working in stores, for example.)

I go to a therapy group and pretty much everyone in there is struggling right now, too.

I think the whole purpose of having a winter solstice holiday is that the short days and weather this time of year are a downer and a holiday is supposed to help to cheer us up.

It's unfortunate that the holiday has become so enmeshed in expectations and stress that it probably makes things worse instead of better. Personally, I'd go spend the month of December in the Caribbean if I could afford it.