World Resetting Randomly

Every time I enter a world their is a message saying the world is unresponsive. After this happens and I exit, if I reenter the world is reset. This has happened to all new and old worlds. I can no longer play without constantly starting anew. This issue has continued through 3 updates. It is currently doesn't give me any warning. One day ill go back onto a world and I spawn at the first spawn point and everything is gone and the world reset. This is getting really annoying because I cant have a world for no longer then a month!  The new snowball simulator world I downloaded to play even Reset leaving me to look at the world before the houses where there! This needs to be fixed.