My survival world is gone.

To whom it may concern,

Less than an hour ago I logged into Minecraft to play on one of my survival worlds, however my computer was lagging for some reason so I exited the world, then the game, and then restarted the computer. When I logged back in I couldn't find my world though, it was gone. 

I don't really know if this is an issue you can help with, but I did find it a bit suspicious that my world disappeared as soon as the "migrating to microsoft account" notice appeared. Before I restarted my computer, that message didn't show on my launcher.

It's not a huge issue unless someone else has experienced it as well, but I thought I'd report it anyway in hopes of getting help. I did spend some hours on that world and would love to get it back.

Thank you for your help!

Sincerely, Fredrika.