Like clockwork, every year. Usually happens 2 or 3 weeks both before and after the winter solstice.
I try to make sure I’m getting plenty of vitamin D. And I try to make sure I’m getting outside for a bit everyday. Exercise helps a lot too - anything that’ll get your blood flowing and heart pumping.
I also make a rule for myself that I’m not allowed to make any big decisions or big commitments during that time of year because the depression can cloud my judgement. Not making commitments is hard with the holidays tho, so if I have to I also leave myself a way out of them if needed. I’ve become an expert at giving a “definite maybe” in response to commitments lol