Itunes deleted half of my library and all playlists?

I was renting 2 movies from the iTunes store and they were going extremely slow, so I paused the downloads and exited out of iTunes. When I reopened it, all my playlists were gone, including the Smartlists, most of my movies, 2 of my tv shows, and half of my library was gone! Why did that happen?? I recovered all my music and videos, but I REALLY want my playlists! I had almost 30!