Hmmm, guess what? The day before it happened, I had fed her half a small can of wet food which she normally never gets

I've been in close contact with my vet and she says that is probably the cause. I've also been on Litter Box Patrol and haven't seen any more blood. Shiloh is still acting normal. In fact she and the dogs got into some trouble while home alone yesterday... ripped open their Xmas presents