Latest update has lost my playlists and other problems

I recently updated to the lastest version of iTunes for Windows (64 bit). When I restarted I agreed to the terms and conditions and to share my library with iTunes and then had to enter my apple ID to log in. When I did I found that my playlists had gone but my library was all there (or seemed to be). I logged out, restarted my computer and started iTunes again but I had to go through the whole process again (terms, share, login) but still no playlists. I tried a previous versions of iTunes library but still nothing.

I also found that when I checked preferences it had reverted to default settings. I changed them all to what I normally use and saved them and logged out. When I restarted iTunes I had to start the whole process (term, share, login) and went to preferences but these had reverted to default again. I also found that if I tried to burn a new playlist to disc it said it could not communicate with the drive.

Since this I have uninstalled iTunes, reverted to the previous version of iTunes and everything is back to normal, except my playlists are still missing. Are playlists stored in a separate file to the library as previous versions should all have my old playlists in them?