I was going to inquire along the same lines as Heart. If you feel energized by people yet nervous around them, it might be a confidence issue. Introverts can be very confident and purposeful in social situations, and extroverts can be very unsure, but the stereotype is that extroverts feel at complete ease in social situations while introverts have no clue what to do. I know an ENFJ who has social anxiety disorder and tends to drink beer to loosen up at parties; she's also afraid of public speaking and voicing her opinions in class.
You seem like an extroverted feeler to me, very possibly ENFP. Welcome, by the way! Enjoy the forum.