Do you think that's a sign of periodic depression? I've been going through a bit of a rough patch, and I was struck by how my mood could sap my motivation to the level where I felt like I couldn't bear to work. It was very revealing; I had often wondered how depression could actually prevent people from going to work, and now I feel like I've come to understand how much that state can interfere with the ability to function. (Not like I didn't already think it was a horrible condition.)

Anyway, not trying to armchair psych, just saying: I hear ya.