That's pretty much what I've been doing; alternating projects. I have a little side project that I've been doodling and it's been helping immensely, as it's simple and lets me unwind. I've got one serious project in the concept stages, a commission planned (need to get to the store for another sketchbook and other supplies), and I moved another sketch card project up to the top of the list and did some research for it. However, I'm not yet ready to tackle that, so it's been put on the back burner. After several days of anatomical studies and concept designs, it felt great just to doodle cartoons for a bit.