Lurker. But I felt something similar to what you are feeling recently when working on the second chapter of my piece, though it's storyboarding. It's not my fav part, but I was faster then with the first episode so I was questioning myself why I was dragging myself to the point of just "No. I don't wanna. I just want to stop."
So I stopped the storyboarding, left it unfinished and jumped to finalizing the panels that I already storyboarded.
Maybe doing another aspect of the whole process would help? You would still be on-task, just a different aspect of it?