As far as I know, Pages does not have an auto save feature like MS Office and some other apps do, so if you didn't save the document frequently your work is lost. What will be lost is the work you did on the document since last saving it.
Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.