You won’t accomplish much in life if you work only when you feel good. In your every day find something to do regardless of how you feel. Not only will you knock a thing off your to-do list, but you will feel better for accomplishing meaningful goal.
If you feel bad regardless of your great performance – sure – it is time to think, question priorities and decide what to change. But don’t let cursed human ungratefulness knock you of the path. Do your work and feel good about it. Then do it again. And again. And again. Until you can look back and marvel at all obstacles crashed by persistent effort of your will.