I know I preach persistence and the importance of working on a project everyday. But it's also OK to take a day off every now and then. Better than OK--it's even good. Rest is good; stepping back from your project for a moment can also be good.
It makes sense, therefore, to take a day off, or a few days off from the program. It's not something to beat yourself up about.
Just make sure you get back to it before too long.