Who's happy making a B?

I am a straight-A student. Right now, I'm taking a full UG courseload and working, plus taking care of/helping my kids in school. Forget about the house being clean. I am facing the reality of a happier state if I accept that making a B in pathophysiology would not be the end of the world. (The other classes are fine.) However, I am applying for NP programs for Fall '10 admission. Any words of wisdom? I need permission to make a B.