Hi there, since you haven't backed up your computer with Time Machine nor there is no previous version of the saved Pages document, I guess you need to utilize professional data recovery software to scan the whole hard drive for it.
iBoysoft Data Recovery Software is highly recommended here. It can scan the hard drive thoroughly for deleted, lost, or missing files effectively.
By the way, you'd better back up your computer by using Time Machine or iCloud storage to avoid unexpected data loss.