How do I recover photos from iCloud that was deleted but my girlfriend

See the following from If you're missing photos or videos in the Photos app - Apple Support

If you accidentally deleted your photo or video, it goes to the Recently Deleted folder. Go to Photos > Albums, and tap Recently Deleted in the Utilities section. If you see the missing photo or video, you can move it back into your Recents album. Like this: 

Do you have iCloud Photos turned on in your iPhone? Check that at Settings > [username] > iCloud > Photos > iCloud Photos.

If that is on, the photos on your phone and on iCloud are the same. If you doubt that, use any computer internet browser and log into www.icloud.com and go to the Photos app there.

If iCloud Photos was not turned on and if you did an iCloud Backup, you can restore the backup to your phone but be aware that it involves erasing your phone and then replacing all of the data on it (not just the photos) with the data from the time of the backup. See: Restore or set up your device from an iCloud backup - Apple Support

See information in If you're missing photos or videos in the Photos app - Apple Support

Since she was apparently using your AppleID, her deletions, including from the recently deleted folder, were no different than if you did it. That deletion was permanent.

Do not share your AppleID with anyone, ever.

If she deleted them twice -- from both Photos and from Recently Deleted -- I know of no way to recover them.