Sometimes if you've been at it really hard, then I don't think a break of a day would kill you, but if you want to break for any longer, then I suggest re-evaluating why you spend time at the piano practicing. As an adult beginner, I've had many struggles with this, but through this website and various other sources, I've come to look at practicing as not "hard" or "a hassle" (I hate when given something to practice you don't like, your teacher says "the sooner you finish it, the sooner you can move on;" this is horrible advice) because whether you realize it or not, how you think of practicing - and thus your success with it or lack thereof - affects
how effective your practicing will actually be. Pianist and pedagogue Seymour Bernstein devoted an entire book to effective practicing based on this idea (he even went on to argue that how you practice can positively or negatively affect all other aspects of your life as well, with which I agree). You need to look at practicing as a process
that you enjoy if for no other reason than because you enjoy being at the piano and the results that manifest from said time spent practicing. Now mind you, I'm not saying that you should practice (and enjoy it) whether you're getting results or not, as I expect such patience of no one, but instead that you should practice always with specific goals in mind and a crystal clear understanding of how to reach said goals as there's no greater motivation than achieving what you want. If your current teacher can't convey this knowledge, then you may wish to re-think what you pay them for.
See the current on-going thread here for some more possible advice: http://www.pianoworld.com/forum/ubbthreads.php/topics/2104593.html#Post2104593