To see a German Shepherd in your dream, highlights your protective instincts and attentiveness to a situation. This is no time for you to be nervous and/or lose control.
To dream that you are training a German Shepherd suggests that you are open to new ideas and/or easily influenced. You make be seeking some reassurance.
Dreaming of being attacked by a German Shepherd means that you have let your guard down and it is time to put it back up.