Worlds Disappeared, even the files.

My girlfriend and I have been using minecraft as a way to see each other and interact with each other. We had a world where we had built many things, and grinded for many things. I hosted our world and we had a lot accomplished. We recently took a break from playing minecraft, and we decided to finally play again, but once I booted it up, it asked me to sign in for some reason, when I signed in, my skin was gone. I checked the worlds, and ALL of my worlds were gone, not just the shared world we had. I just need it back.