Joy is a state of high energy consumption. It cannot be maintained therefore for long. You have to reload and relax and regenerate. So I guess your state of tiredness indicates a lack of energy and that causes a lack of joy. In order to be free enough to enjoy things and reload the batteries the depressing routines must stop. They also cost loads of energy. A boring schedule, repetitive responsibilities and uninspired tasks only cost energy, they do nothing to back you up. So I tend to break the wheel of schedule and running the same rails by hopping away from rails and the command of the clock.