all mobs despawned , even named ones

i played minecraft a day or 2 before i saw this. everything was fine , all my animals were there , pandas , horses , dogs , cats , villagers. everything i had was there. i logged in the next day and everything was gone. i went in my basement for whatever reason and my armor stands were gone. i went upstairs and looked outside the windows , horses in pens are gone. farm animals gone. bunnies in a hole with glass over the hole were gone. goats gone. everything was gone. i have no clue what happened , everything else is fine. buildings are there but all the animals are completely gone. even the ones that are name tagged.