Next time, take a lunch and tell anyone who's nosy enough to ask that you're testing to see if you're gluten intolerant. And yes, you are, so you don't have to explain in the future why you're not eating crap from work.
Unless you're concerned about calories (and pizza has them in spades) eat a normal primal dinner. If you're concerned about the calories, then eat a lighter primal supper. But dont' stress about it after this. What's done is done.