Energy and mood levels change with the seasons. As some of us in the United States begin to get colder temperatures, perhaps you want to change up workouts. If it doesn’t screw with longer term goals, your desire for change may be probably worth honoring.
That doesn’t necessarily mean doing less, it may just be different. I think I get more motivated for a long training plan in the winter months because I know I’m less likely to spend my days being active if it isn’t on a plan and in furtherance of a goal.
Maybe you can run outside later when there is daylight (for those of us facing long hours of darkness), or maybe it means heading inside for a dance class, allowing someone else to keep the energy up.