I suffer from Seasonal Affective Disorder, too. I want to burrow down in the basement and sleep like an old bear. Problem is, it can spiral into depression and worse, so I do like Pat does. Get off my butt and just get out in the sun whether I want to or not.
Strange thing about it, winter is my favorite season. I love late season muzzleloader deer (no tag this year, first time in 10 years), ice fishing, stomping thru the woods in the snow, camping in my big ol' canvas tent with a wood stove crackling....if it is outdoors, it's wunnerful. But overcoming the inertia is tough.