It sounds like worms to me, and I thought that even before I read what your DVM instructor said. I thought that because of the mucous you metioned. That is often a sign of worms. Could be something else. But either way, she can' be feeling to well, so a trip to the white coats is in order. They will likely ask for a 'sample,' so don't forget to take one if available in the morning!

I don't know how much cat poo she would eat to get like that. Mine sneak in to the litter box now and then, I catch them in the act, never see any problem from either end but then I am catching them right away. They sneak in while I am cleaning boxes at night and the baby gates are down; seems like they know my routine as well as I do!