All nearby mobs despawned

I logged in and almost all of my nearby mobs have despawned except for one cat. From villagers (cured and normal ones), nametagged zombie, chickens, cows, sheep (both in the pen and one with a lead) and cats. All of them are gone, I logged out earlier today with the save thumbnail having my Cleric villager but when I logged in, all of them were gone.

 

I hope this can be fixed.