Mistaken use of Control-Y (CTRL-Y) to Redo

I recently thought that I lost hours of work (in Adobe Illustrator) when I accidentally used control-Y (CTRL-Y) to redo something after I used control-Z (CTRL-Z) to undo a change. When I used control-Y, a white background with only fine outlines of my work remained. After trying to use control-Z (to undo my mistaken use of control-Y), and finding that it did absolutely nothing to resolve the problem, I began to experiment with the remnants of the work.

I selected the entire image (which was only fine lines), used control-C (to copy the selection), then opened a new document and pasted the contents using control-V. Like magic, all of my work was on the new document - details, colors, everything! I can only theorize that the original work was not really lost, only hidden in a way that I was unable to recover on the original document.

Wondering if anyone else has a solution for the mistaken use of control-Y in an Adobe Illustrator document.