I'm not sure that you are doing anything very wrong, but perhaps your body is not quite tired enough to fall completely asleep. Does this normally occur after you have woken up during the night or at the beginning of the night when you are first going to sleep?

Also, how would you characterize your emotional state during these 30 minutes? Curious? Calm? Anxious? Scared? Some of this info might help identify why these HH aren't transitioning into the dream state.