Pets and Leaded Animals Disappearing

I loaded into my single player survival world today and saw my named cat had disappeared from my house, as well as my horse (not named but wearing a saddle and armor) disappearing from it's stable and 2 sheep that were leashed to a fence vanished too. Nothing could have killed them and they shouldn't have despawned on their own since they were tamed or on a lead. I miss my cat Pooper ):