iTunes says I have 10GB of music on my iPhone 5, but I have NO music synced. How do I fix this?!

I recently deleted all the music on my iPhone 5 from the newest version of iTunes (I can't even figure out how to tell which version that is on this thing). My phone shows that I have no music on it yet iTunes is still saying I have 10GB, even though nothing comes up on the "on this iPhone" section. How do I fix this? I can't add anything to it anymore. It keeps saying I'm over my limit but there's nothing there.