My photos disappeared from my Samsung S5 SD card. Trying to recover photos or find hidden files

My photos disappeared from my Samsung S5 SD card. I know SD cards get corrupted, but there were a couple of weird things that happened in conjunction with the disappearance. I saw a message on my screen briefly saying something about my photos not being gone. About a week later I saw them again just once when I went to look at other photos on the Google + app. I saw a suggestion to try to do a disk check on a computer to recover corrupted files. Disk check says the info cannot be directly accessed.I also have read that some files can be hidden. I need some help with this. Any ideas?