Icloud Photo's

No one can answer without details - what are your iCloud settings on each device

The Most likely guess is that you are using iCloud Photo Library which is a syncing service and as documented all changes (additions, deletions or edits) made on any connected device are made on all connected devices

iCloud Photo Library - Apple Support

iCloud Photo Library automatically keeps every photo and video you take in iCloud, so you can access your library from any device, anytime you want. Any changes you make to your collection on one device, change on your other devices too.

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I didn't touch any settings. is there any way to get my photos back?

iCloud Photo Library may have been enabled by default on your iPhone, if you just upgraded to iOS 11. Check the settings:

• On your iPhone, iPad, or iPod touch with iOS 10.3 or later, go to Settings > [your name] > iCloud > Photos, then turn on iCloud Photo Library. In iOS 10.2 or earlier, go to Settings > iCloud > Photos.
• On your Mac check System Preferences > iCloud > Photos > Options.

Get help with your iCloud Photo Library - Apple Support

If iCloud Photos Library has been enabled on the iPhone and the Mac, when you deleted the photos from the iPhone, they have been deleted from iCloud and the Macs library as well. If they are no longer in Recently Deleted, because you emptied this album, they will be gone.

Then you should restore your Photos library from the last backup you made, before you deleted the photos from the iPhone.

As documented in the link I posted open the recently deleted album and restore them form there within 30 days of deleting them

Even the photos and videos you delete on one device, delete everywhere that you use iCloud Photo Library. And if you want to get a photo back, you can restore it from the Recently Deleted album for 30 days.

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