iTunes stops responding when I connect my iPod.

Background info: when I disconnected my iPod awhile ago, all of the music disappeared. I *did* safely remove it. However, while it was disconnecting, I somehow unlocked it (the hold button....do you know what I am talking about?), and then it said "Okay to disconnect" (or whatever that message is) so I disconnected it.

But then as I was unplugging it, it connected again or something. But it was too late. All of my music was gone.

Now whenever I plug it into the computer, iTunes does not function. I can see all the files on my iPod from when I was using it as an external backup drive, and can access those through finder. But nothing involving iTunes is functional.

Help, please?

Thanks in advance