I find that if I step back from the project when I'm sick, not only do I recover faster, but I often think of novel ways to solve a problem (or realize the solution was under my nose) by nature of taking some time away from the screen.
You'll find that stepping back from a problem, even when not sick, generally can help your overall perspective. I personally like to take walks and focus on things other than the problem at hand; this almost always results in clarity for me.
