Two different sheets becoming one

Hello there!
I have a huge problem. So, I created a music sheet on Musescore 3.0, then I created another sheet with the same name, but it was empty. For an unknown reason, the two different sheets became one sheet, and the new sheet after the ''merger'' is empty. I am going crazy, the sheet took me 3 days to create, and it is just empty.
Is there any way I can undo the ''merger''???????????
Please answer!