All of my worlds are gone.

It first started with my world not letting me play it. When I clicked on the world, it would act like it was loading then it would kick me out of Minecraft completely. 

I signed out of my Minecraft account and re-signed in, as to try and solve the issue. When I came back, all of my worlds were gone. I tried swapping from "External" to "Application," but that was no help. 

I looked into my minecraftWorld files and nothing was there. 

I would appreciate help on this, since I have worked for so long on these worlds, and would hate for them to be gone, as well as the worlds I payed for.

Minecraft Pocket Edition