Pocket edition keeps crashing

I click on my favorite world that I have been building for years and it acts like it's going to load and then the app completely crashes! It closes out the app completely. - I had just "tamed" my 5th dog when this happened. It started acting slow and then crashed and I have not been able to get in it ever since. 

I did offload the app from my iOS device and then reinstall it and nothing is working. I tried to duplicate the world and it still gives me the same problem. Can we save this world??  It's seed -1820383455 it's titled "Josh's world". It has probably 438+MB