iTunes resets itself back to old files when shut down
So I don't know what happened a while back but everytime I exit out of iTunes or shut down my laptop, when I turn it back on or open iTunes again, the iTunes library is of one from about 3 months ago. All my cover art gets reverted back to nothing and any tag changes are reverted to the original style. Also, when I connect my iPod, it deletes any new playlists made since then, it reverts my play count (so my play count never goes up), and old bands that I have deleted re-appear on my iPod but they are just shaded grey and can't be played. Does anyone know how to make iTunes stop doing this?
iPod touch (4th generation), iOS 5.1