Issue with Music not showing up

So on my iPod Touch 5th gen, I've had lots of issues with my music. I've always resolved it by simply restoring it to factory defaults and putting the music back on - but I really don't want to go through all that again.

So what happened was I tried to put new music on my iPod, and then I came back a few minutes later and all my music disappeared from my ipod. If I tap "Music" on my iPod, it acts as if I don't have any music. However, on iTunes under On My Device, it shows all my music there. So technically my music is there, but I can't access it?

Any help would be greatly appreciated.