I've had that problem, looking around in the forums I found that you need to make sure you phone is updated (settings-update) and then do a reset. Should do the trick as it did for me.
the quickest fix to restore the 3D i've found is to go into camera (hold down the camera button on the side for a second or two) and toggle from 2d to 3D (if it's on 3D go to 2d then back)