How do I retrieve my Pages document?

Pages document. Writing my memoirs and I did a stupid thing. I was trying to replace an updated page in the document. I stupidly gave it the same name as my document, when I clicked replace, it replaced the entire document with the one page, even though I had the page highlighted. How do I retrieve my document. Fortunately I did not lose it all, but several days of work which I could never recall.

Any help would be greatly appreciated, Thanks so much.

Bill B.

[Edited by Moderator]