Backups

I didn’t recognize a device on my account so I (forgot it?) and deleted its backup. I was confused on when it said “deleting its backup”. It sounded like all my stuff was put on this phone I did not recognize. I was afraid I had sold an old phone and they had all my account information and things of the sort. As a little time has passed I think it deleted the pics and stuff I made with that phone at that time and it’s deleted from iCloud? Can I recover it? I’m super upset with myself becaue I did not understand this and it has deleted a lot of valuable pics of my children I cannot get back.