Where did these photos go & how can I get them back?

Hello! About three weeks ago I took about ten photos on my IPhone 4 & about a week later they were gone! They're even gone from my photo stream & ICloud (where I usually save most of my photos). I did not delete them, they were there in the morning & then when I went back a few hours later, they were gone. Only ten photos that I took in one area. I've checked my other devices to see if my photo stream or ICloud had some how shared & saved them, but they're gone. It's really upsetting, is there any way to get them back?