So i was listening to music on my iphone today and noticed that some songs that were in my synced playlist weren't showing up on my iphone. I went into itunes and no matter what i did, those songs would show up as on my iphone in itunes, but no on the iphone. so, i unsynced all music. then, when i resynced, no music would show up at all. it all appears grey. i've tried manual management, and it acts like it's letting me add the music, but there is no load time. it just registers it as added when it hasn't actually added any files to the iphone. Help?