Catfilter: Cat is urpy, vet is closed, how worried should I be?

My darling dearest kitteh is 5 years old, and seems to have some kind of stomach issue. Our vet is closed til Monday, so in the meantime -Is this a potential emergency? -If not, how can I help her poor little belly? Slightly gross details below. [more inside]
posted by like_a_friend on Jan 26, 2013 - 14 answers