I know your pain, happened to me once too. I had an encrypted /home partition (Ubuntu) and the upgrade shouldn't have been a problem, but something went wrong and I lost everything (I suppose the alternate install cd was the problem). I learned two lessons:
1. Don't encrypt your /home directory, if you need encryption, use TrueCrypt.
2. Always make back-ups (although I have to admit the last back-up was some time ago :P)
Anyway, good luck restoring your data!