Diagram content lost after copying to new page – previous versions altered

Hi, my entire history seems corrupted after I copied my work on a diagram. I selected all my blocks and arrows and pasted them onto a new blank diagram page, but not all the content followed. Now I’m left with only about 40% of my work, and even when I open previous versions, all the arrows and text are gone. I also can’t remove the white diagram frame anymore. How can I recover the original version of my diagram?