I'm going through it now. I have a commissioned piece I'm working on (a 16" x 20" entirely 2D print project where a bunch of aliens are dancing), but I can't seem to get into it much. All I want to do is create another 3D image and do some postwork on it, or maybe write a book or something. I think it's partly avoidance or reluctance of the thing you have to do and partly enthusiasm for the thing you really want to be doing right this moment. Totally natural and very common.