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:
iTunes: Restoring iOS software
To restore from backup see:
iOS: How to back up
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:
Downloading past purchases from the App Store, iBookstore, and iTunes Store
Also, if the photos are not in a backu[
- If you used PhotoStream then try getting them from your PhotoStream. See that topic of:
iOS: Importing personal photos and videos from iOS devices to your computer