When I delete photos from my camera roll on my iPhone 5S, they delete from my photo stream too.

I recently came back to my iPhone 5S, so I'm not aware if this is something new or not. I have always been one to delete my photos on my camera roll after I have seen them move to my photo stream. Just these last couple of days I have noticed that everytime I have deleted a photo on my camera roll, it disappears from my photo stream too. I have uploaded my pictures to my Mac just to back them up for sure, but then they still don't come through. Is there something I need to switch? Maybe reset the phone?

My phone has been updated recently, too.