[Carina]

Could it have been diarrhea?
If it's really pus, that would seem to be a very serious infection that really can't wait a week. If it's diarrhea, it's something that may pass (so to speak) and there's things you can do for diarrhea...

Cats are pretty stoic & often won't show signs of physical stress until they are truly feeling miserable. Dehydration, (gently pinch skin on back, it should spring back quickly) pale gums, not eating, drinking or grooming, painful stomach, listlessness....if you see one or more of these things going on, then she really must go to a vet.

I'd make the vet appt, if you haven't already, and then just watch her carefully.