Phew, good. I was afraid your vet may have prescribed an antibiotic toxic to
GPs and may have inadvertently killed her. Baytil is fine though. So I'm thinking it was Pyometra. She probably was pregnant and either the babies died and she retained them or they were aborted and you either didn't see them because they were still very small or she ate them. Either way it ended up in tragedy.
I know you have already learned the hard way but I have to say it again. Please, no more petstore or breeder pigs. The only way we can stop them from harming more animals is to not support them or the Breeders they buy from.
Still, Cream should have a vet check. She could be harboring am upper resperitory infection (URI) especially since it sounds like Peaches had one.