Never, I repeat never upgrade your WordPress as soon as a release is out! (Listen to Leanne, she knows her stuff!! ) It will cause you much anguish, make you drink too much coffee, talk to yourself, and make you even bribe others to fix it for you! I’ve learned my lesson,  of course, I had to learn the hard way and lose a few posts, comments and such…but at least I have my blog back!!!!