Lost everything after iPhone sync--How can I get it back? I plugged my iPhone into my computer last night and opened up iTunes.  It said I needed to sync and download the latest version. I clicked ok.  After all was done my iPhone has been set back to Decemeber. 

Therefore all my photos since December are gone.  All my contacts - gone!  All my conversations on Messages and WhatsApp - gone!! This is a major issue as my iPhone is part of my work scheduling. 

What has happened?  Can anyone tell me what I can do to get it back?
Also why did it do this?
If you've backed up recently, you might want to do a full restore, which will wipe your iPhone clean and reinstall iOS. After it's done that, it will offer to restore from a backup, reinstalling all apps, calendars, email accounts, etc.


http://support.apple.com/kb/ht1414