Photos suddenly disappeared and then reappeared out of order

So a little while ago, for some reason my iPhone out of nowhere removed all the pictures from my iPhone. I wasn't even using my phone when this happened and it definitely wasn't self triggered. I didn't even notice this happened until I picked up my phone to try to upload an image to Facebook. However, the photos then started coming back bit by bit all by themselves. It took a little while for all my pictures to come back. When it was finished, I noticed my photos are in some very bizarre order that makes absolutely no sense to me and now it's an absolute pain to find pictures in my camera roll. Has this happened to anyone else? I have no idea and I'm very worried that my entire camera roll is completely screwed up now. I have an iPhone 5s if that helps.