Well, let me see if I could at least answer it. I think you've heard it already, but I'll give it already.
We all have a range of both; some are more introverted and other extroverted. Being a pure I or E is rare. You, are what's called an Ambivert: a person who has roughly both measures of Introversion and Extroversion.
Do you on the one hand feel energized by being with and conversing with people, but on the other, you would soon tire from it. And, vica-versa?
Since you seemed very concerned about it do you feel that you might have a split personality disorder? Or would you rather be one or the other?