Yes, I get them too :-(.
What I have noticed is that as the kids have gotten older, more of their activities are out of the house. Having to take them here and there kind of interrupts that winter isolation and has gotten us around more people.
When they were younger I took advantage of library activities (movie afternoons, visiting zoo animals, etc). Our library also has a blue lamp (?) the light that is recommended if you don't get enough sunlight and wards off SAD. You can sit by it while kids are in activity.
The jumpy places usually have discount hours so the kids can burn off energy...
I've been blessed to have a network of pretty good mom friends...one goes walking with me twice a week. I don't want to let her down and I enjoy our talks, so it forces me out. On days when it is too snow covered, icy or cold, our local high school allows residents to use indoor track. It can be used daytime or evening, so we even meet there or I go alone.
I have another friend who does The Bachelor viewing parties. Not quite my cup of tea, but she "forces" me (wink,wink) to come enjoy her delicious treats she puts out and enjoy a glass of wine and before you know it I am commiserating with the other viewers about this long winter and having a great time. I have also branched off with other close friends and have a viewing night of some of our favorite shows.
Another mom group, we do movie nights 1-2x over winter and watch teen favs from our generation (Breakfast Club, Something About Mary). Which when I host forces me to clean and get creative for a theme, LOL
Being an introvert, it is hard for me to put myself out there. But I realize if I don't, I isolate and that can spiral down to an ugly place.
So for me, it has been helpful to put effort into connecting with others in group activities, and from these I have found some close friendships that appeal to my introverted self and that have managed to use the 'buddy system' to help each other through winter.
We're in February.....we're getting closer to the end :-)