paste destroyed my document after up date

I updated a few days ago. This morning, I pasted one word from one document to another within the same project using control c to copy control v to paste.

When it pasted, it deleted about an hours worth of editing/ writing and pushed the lines over each other so two or three paragraphs are un readable. Help. I need to get my work back.

Mod note: Locking this duplicate to keep things tidy; please see the thread here: viewtopic.php?f=30&t=24485