[ja27]

Assuming you're in the northern hemisphere, this is a horrible time of year for depression. Short days, cold weather, etc. You can fight this with exercise, diet, getting outside, getting as much sunlight as you can (or using those full-spectrum lights), etc. So that's one cause.

Then there's the general case of getting stuff done. I try different things and a few have worked for me. Go work somewhere else. Like I go sit at a McDonalds or a sports bar and I can focus on just code for an hour or two. That's not enough to get stuff done but it gets me started again. When I'm stuck I like to find small tasks and just start completing them. No matter how small, the act of crossing anything off of my list feels like progress and I can get going. Then I also like to end my day by writing down small discrete steps for me to do first thing in the morning. Not big "build a new version" stories but small stuff like "fix X bug" or "resize icon Y".