I am going to throw a new angle at you. It might be way off base, even inappropriate. But at the risk it might help you put a handle on it (as it did for me) try out the personality test here: <A target="_blank" HREF=http://www.4degreez.com/misc/personality_disorder_test.mv>http://www.4degreez.com/misc/personality_disorder_test.mv</A>

It showed me with traits of schizotypal personality. My pdoc agreed that the description fit me, but she prefers to think of the personality "disorders" as "characteristics", or ways to describe personality, not pathologize it. Some of my traits sound similar to what you describe for yourself.

Anyway, this was helpful to me and started me on the road to a lot more important self-discovery. What was helpful was realizing that the cluster of traits was so common that they even had a name for it. I was not really unique and alone with my social discomforts.

Here is my test result from a few minutes ago. I have taken it several times over a few months and it is very consistent.
Disorder | Rating
Paranoid: Moderate
Schizoid: Moderate
Schizotypal: Very High
Antisocial: Low
Borderline: Moderate
Histrionic: High
Narcissistic: Moderate
Avoidant: Very High
Dependent: Very High
Obsessive-Compulsive: Moderate