Every mob died and cloud on land

I think I'm done playing, EVERY MOB INCLUDE EVERY VILLAGER I CURED DIED, I HAVE LIKE 104 DOGS, 78 VILLAGERS, LOTS OF OTHER ANIMALS!!!😭😭😭😭Imma go and depress now... 😭😭😭😭😭 I made a copy of the world and another copy, but if I login that copy world, it is still the same, so I only have I copy world that I haven't touch.. The world that everything is still alive.... For now