how to recover deleted photos without backup?

Recently I went on a trip and took photos with my iphone 5s (ios 9), every night I would submit those photos to the icloud shared photos feature and then delete them from the phone because with 12 16Gb one has to find ways of optimize storage space. I decided to show the pictures to my family yesterday and it turns out there are missing pictures. I want to know if there's a way of recovering the files, I didn't backup precisely because I thought icloud was enough. The photos were taken 3 weeks ago.