My World is gone

I loaded up minecraft 1.15 and logged on to a world i was working on previously in 1.14.4 and everything loaded correctly, even the villager trades. I checked the new blocks and placed then destroyed them just so i could get a look, I went back into 1.14.4 to avoid any bugs, and everything was deleted and reset. Yet i still had all my stuff in my inventory, I also tried loading it back up in 1.15 and still everything was gone. Can you fix it? (Yes the world was backed up but the backup is gone)