All songs on ipod deleted and not recognized by MacBook

Hi,

This morning I was creating a new playlist on my ipod classic and when I unplugged it all of the songs were deleted! Now, when I try and plug it in to my MacBook Pro it is not only not recognized by iTunes but the computer doesnt recognize it AT ALL!

I have tried resenting it several times and nothing changes. It turns on but there is nothing on it!

Any help is very much appreciated!