It's probably something wrong with the Bluetooth inside the controller, some of my controllers work but some don't, it's just how it is. But one thing that worked for me was to reset the network settings on your iPad and pair it with your controller again. Also try pressing the reset button on your controller you need a paperclip or something narrow to reset it.
I know how it fells, but I guess we could always make a new world. Rip to all our pets and villagers that got erased with our worlds.