I have to restore my ipod, will it delete all of my data, if so how can I back it up???

I have to restore my ipod, will it delete all of my data, if so how can I back it up??? My ipod won't let me delete any photos, or download any apps, so I turned it off and back on when the itunes and usb symboyl appeared I just download Itunes, and i can only restore it, Will it delete everything?!?!