The notion of taking a "back off" week is pretty well-established around here (even if it isn't "official" CrossFit doctrine (LOL . . . other than "constantly varying functional exercises executed at high intensity" . . . there *is* no official CrossFit doctrine)).
Search the boards for posts by Larry Lindenman on the subject of "back off week". He's articulated the idea better than anyone else.
After 8 - 12 weeks of steady work, you're due for a light week.