My Ipod Nano Turns On And Off ( read message)

Hello,
I was listening to music on my Ipod Nano and I turned it off correctly because I had to go,and when I took it out again it showed the apple sign then went to the menu for about 4 seconds then shuts off and does the same again and now it wont stop,and when it went dead I charged it and it charges but doesnt connect to i tunes or the computer and when I un plug it from the USB cable it does the apple sign and shuts off again until its dead.
How do I fix it ????