Villagers and tamed horses despawning

I started my game on a regular world (not realm), and after some days in-game i started a villager farm. As well as i got a horse with diamond armor and a seat.

It was all going well, i had some good enchantments, until one of a sudden, my villagers despawned, as well as, the horse.

The horse and the villagers were in a home, villagers were underground with no possible way to escape. They also had a bed and a small harvesting area.

I didnt really care and moved onto another village. This time, i made the farm better and got some villagers with mending, prot 3, fortune, thorns, etc for 1 emerald. It was all going great, until when i woke up (this day), all of them despawned. (Including my horse which was on a safe place)

 

this is getting really annoying, if theres a way to fix it, or its a code problem, please let me know, thank u.