After downloading 3rd party packs I can no longer play game.

I was playing on my single player world and decided I wanted to try some Add one. I downloaded one add on which basis sly added baby parrots and boats with chests. I also got about 20 resource packs. Everything was working fine until one day when i tried to open my world and a message came up saying updating packs. The game then returned to the world select screen where, no matter how many times I clicked, I could not get in to any world. I have since gone in to the storage section in settings and deleted all packs (including the ones I got from the in game store) and this problem still persists. What’s more when I go in to the individual world setting I still get these packs as an option to apply them. 

It it should be noted that this problem does not happen all of the time. When it does happen restarting the game sometimes fixes the problem sometimes doesn’t. However this is a game breaking bug and extremely annoying. I don’t think I have downloaded a virus either because no other aspect of my device is out of the ordinary. Can someone look at this soon because I am thinking I may have to uninstall and reinstall the game but I don’t want to lose my worlds.   (I have an iPad mini 4)