Search the Sd card manually from the file explorer and check all the media and DCIM folders for your stuff. If they are not there then I'm not sure what else to tell you. The best thing to have done would've been for you to make a backup of everything before you accepted the update. If you find the content, make a backup of your data so you will not lose it again. Good Luck
My GS3 sleeps in the bed and I make my girlfriend sleep on the couch