music on my ipod touch got deleted

Do you use iTunes? If so, it automatically backs up your music library so you can avoid situations like this. I hope you use this application.

If you don't use iTunes, do you back up your data in any way? Did you buy your content through the iTunes Store? If so, you should have a receipt for the transaction and possibly retrieve your content.

Itunes does not automatically backup your music library.

You need to make your own backup copy.

If this happened when you added new podcasts, and the music all shows up on itunes but not on the touch, then plug it into the computer, open itunes and click on ipod touch you want to view. Then chose to sync podcasts. I had it on sync, then manually put on podcasts, and I think that is what messed it up. I reset it on sync and chose how to sync the podcasts (still leaving music and the main setting on "manual"). Then I clicked "sync" and now the music and videos show up on the ipod touch (no backing up, no resetting). Hope that helped