This is the warning I got when I deleted a new album had made:

You're right-- the pictures aren't deleted-- just the album. An album us just a list of pictures you'd like to see together, and that list is gone, but the pictures that were on the list are still in the Library.
As Yer_Man suggested, a backup that you might have made is your only recourse.
If you don't use iCloud Photos, but you have Settings>Apple ID>iCloud Backup turned on, then you may be able to recover data from the last 30 days or so at iCloud.com, but you would need to look at the date of the backup to be sure it's from before you lost the albums. You should look here:
View and manage iCloud device backups - Apple Support
This requires you to erase everything on your phone and replace it with the backup, a sort of "nuclear option." To me, that sounds more disruptive than just trying to round up the pictures.