Glad to know you in here who had the same struggle as mine.
But what I realized to what Sir Terry's advice was that,
There is nothing wrong about being introvert.
Again, these words comes up to my mind..
What your location considers introvert etc, may not be "introvert" in another location or to the world on a global scale.
There is nothing wrong at all in being an introvert. I am one of such person. I just don't have the outgoing nature in me and I like cause it makes me unique.