I think a bug happened in my world (Bedrock/Pocket Edition)

Hey, so I have a world that basically 2 years old now. Then I opened my minecraft on my phone, then when I opened it everything got reset. There's no account logged in my game despite being logged on my account when I left the game yesterday and also changed my controls to default. So now— i logged into my account again and open the world menu, the world's are still there then I opened my world and when I looked around, all of my pets, villagers, paintings and such disappeared. My last back up was 1 month ago and when I checked that world, it didn't have the same problem.

Is there like a way to get back all of the mobs that disappeared? I really don't want to just go in my back up world since i already did a lot of work in my world compared to the back up.