Q: 7th generation playback speed slow on music

Suddenly my iPod Nano 7th gen started playing back my music slow.  I don't know what happened or how I fixed it.  It played back normally through my computer.  I don't know how it happened or how I fixed it.  Can anyone help me figure it out.  I know about playback speeds in audio books.  Not supposed to happen in music playback, right?

Thanks