The depression/sadness/dread makes people want to conserve energy.
We work on effort and reward cycles. For an ordinary person, doing these regular activities is easy because it brings a significant improvement in their day (as a reward ) . For a depressed person the improvement in gloominess might not be worth the effort put in . Even if you feel better , you are still in the "gloomy" category after these activities , that's how the brain thinks .