You are out of luck. Your iPod experienced a problem and is now erased, All you can do is restore from back.
Connect the iOS device to your computer and restore via iTunes.
For how to restore:
To restore from backup see:
If you restore from iCloud backup the apps will be automatically downloaded. If you restore from iTunes backup the apps and music have to be in the iTunes library since synced media like apps and music are not included in the backup of the iOS device that iTunes makes.
You can redownload iTunes purchases by:
Also, if the photos are not in a backu[
- If you used PhotoStream then try getting them from your PhotoStream. See that topic of: