My Ipod erased all my music music automatically what happened?!?!

so im in india, i havent attached my ipod to any computer or anything. i was listening to it on the bus on my way to my cousins house, then the battery died and the next day i put it to charge and once it was fully charged i tried to listen to it and it hard zero songs!! but the videos are still there just the music is gone

remember i dont have access to my itunes library as my computer is back home and im on holiday, i dont get what happened