Crashing, but thats all!

Ever since the last update, my worlds crash more easily, and as soon as I hit the join button on my new-er worlds, its been crashing immediately. If I do get into the world, it only allows me to play for 3 minutes before shutting down again. Id appreciate if you looked into this problem! Thank you

Crashes! :( about Minecraft: Pocket Edition, v1.1.5