Photos missing on photos app but viewable in other apps

I have the iPhone 5S and my phone glitched out one morning and then it seemed as though all my photos got deleted when I tried to view them through the photos app. However, I continued to use my phone during the day and I noticed I can still view and send the "missing" photos through Facebook and other apps. Has this happened to anyone else before and is there anyone I can transfer the photos back to their original destination?