All my pets are gone

I was playing on my world and doing random stuff, and I have these horses and mules and stuff in a pen built into my house. I go to them to get my pickaxe I was keeping in one of the mules chests, then I realise their gone. Not a single one there, without a single thing of mine. I then go upstairs and my cats and wolf are also gone. Please do something about this, I need my animals back