Lost music and apps after iOS 5.1 update! Please help!

I have an iPhone 3 (iOS 5.1) and iTunes (10.6.1), both of which I updated last night. Now, all of my music and apps are gone on my iPhone. I've tried syncing, and it did not work. How can I get my music and apps back? All of my messages, contacts, pictures, bookmarks, etc. are still on the phone - just the apps, music, and videos are missing.