i've been on it all day on the internet, and using all my applications but i haven't listened to the music since yesterday. i just clicked to open my music and it said i had no music..? all my apps are still on it.. i plugged it into the computer and it automatically starting to sync. when i was done it still said i didnt have any songs.. all my songs on itunes are still there- so then i manually synced it again but still no songs on my ipod.. what happened?! please helppp!