I'm learning psychiatry now (I'm a med student).
I am diagnosing myself with squizoid personality disorder. Mixed with high anxiety levels and some depression. Is this what I have since I was a litle child? Probably.
I read the wikipedia article about squizoid personality disorder, besides it being very exhausting (I think it's a very good article) I saw myself so much in that article.
And it not only discribes the social withrwal and the cold emotional appearence, it also discribes the intense feeling of a more close relationship and the need to protect the self. Secretive with a inner imaginary world:It have always been me.