Lost Playlists

iTunes has been behaving strangely lately. Some playlist titles are being repeated with a number 1 after it but when I look into either the original or the copy, they are empty. It's not so simple to go to the folder and drop them in again because they didn't all have the same album title, they are scattered in different folders. Does anyone know what's going on here and is there a simple way to tell iTunes to reassociate the playlists?