All my worlds got deleted

Hi so there is a farmland thing I could download and I did cuz it was free but when I downloaded it my game kicked me out of my account and when I got back in this thing popped up that said would u like to keep ur storage in external or application and there was nothing on external so I clicked application and it brought up a really old world and now all my worlds are gone and I don't know how to fix it please help and I tried putting it back on external but there still isn't anything there I checked my files and I still have the files for my old worlds but they aren't on my game