I have a personal work that I have had for years at this point, and I log into it today and I find my stuff gone but I'm in the same place.

I made a world in maybe 2017-2018 and I have worked hard on it. Today, I logged onto the word to see that my stuff is gone. Meanwhile, I had Stacked Netherite armor and borderline Op tools. My inventory is empty, I traveled to find new things regarding the update, and this is what I got instead. I do not want to start over as I worked hard on that world and I don't know if I can put myself through the pain I've felt another time. PLEASE Help.