The issue you are experiencing seems to be consistent the sporadic data loss iPhone/iPad users have been experiencing after upgrading iOS.  We have done some research online and have found a couple of articles that may help you restore your data:

 

http://www.pcworld.com/article/241806/did_ios_5_delete_your_apps_music_and_data_heres_help.html

 

http://www.gottabemobile.com/2011/10/13/how-to-recover-lost-apps-after-ios-5-upgrade/

 

Are goal here is help you get your data, please let us know if this was helpful,

Support Team