There are a couple of cures for the winter blues or cabin fever or whatever you want to call it.
The one I've found is to reserve about half an hour to an hour a day to just relax outdoors. Wrap up and go enjoy something outside. It's really quiet and peaceful during winter and I've found a profound joy in reading outdoors during winter.
Spend more time with people. One of the best way to raise spirits. Doesn't need explanation.
Spend your downtime doing what you enjoy. If it's dark outside and you're stuck indoors, spend that extra time doing something you want indoors. Learn a new hobby, read a book, exercise, cook, play an instrument. Whatever.
Solitude provides a lot of freedom from others, but at a price. There's no one to converse with and possibly keep you sane. Over thinking without judging your wandering mind can have psychotic repercussions in the worst cases.
I guess it's about mental stability really.
Bad ideas: Drinking alcohol, overeating, excessive sleeping. Sounds like the holidays are in the wrong months for the northern hemisphere.
That visor really is horrible.
Don't worry, the winter solstice is only a couple of weeks away. Before you know it days will be getting longer again.
Why does the sunrise so late?