Where did my minecraft worlds go?

So one day I updated my computer and then logged on to minecraft to find that my minecraft worlds disappeared.I was really upset since I wanted to play on them. I dismissed it at first but today someone told me that his phone updated and all his worlds disappeared. I have updated my computer before and never has this happened. We both play on bedrock so I am wondering if it has something to do to that. I also want to know if I recovered them. In case it is important, I didn’t export all of my worlds.