Backup catalogs wouldn't have helped with this problem anyway, but naturally, you shouldn't delete backup catalogs for a while.
The solution to reconnecting the folders is given here: Adobe Lightroom - Find moved or missing files and folders
The photos are not in the catalog. They are in folders on your hard drive. The catalog is a database that points to where those photos are located. If you deleted the photos then you'll have the previews that Lightroom generated, but the photos are gone.