Why does my iPod touch keep going back to the main menu when I click on the music icon?

I have a 3rd generation 32gb iPod touch. I had it plugged into the laptop earlier today and I think I unplugged it while it was syncing by accident. It does an automatic sync, but it does not sync music, or videos or anything, I think it just connects to the computer. I just tried to play some music, but the screen said "Updating Library" then it briefly shows the artists then a few seconds later it automatically returns to the main screen. What can I do to fix this problem?