Installed Itunes 11 and my music has vanished

Just installed Itunes 11 and synced my phone and the only music left is the itunes purchses. All my other cd's have vanished but far worse is the good old fashioned LP's that i spent ages digitizing have vanished. Major pain in the bum. Where are they and more to the point how do I get them back. They are not in any itunes folder anywhere.

Thanks