When I'm in this mode, I tend to stay in it. However, much like Skeezkys I follow the train of thought, "You don't have to like it. You're just required to do it."
Something that helps me to do this is to motivate myself to do something I enjoy before doing the things I'm not in the mood for. It energizes me just enough to do what I have to do.
What do you enjoy that you feel up to doing?