I have no friends and few acquaitances that I tend to lose as time passes. I have never had a girlfriend and I am quite sure I never will (I am 24 at the moment). I have been a very lonely person throughout my life. I also have a tendency to depression which adds to the problem because it kills my willingness to work on solving my problems. Unlike you, I am physically fit (not handsome or anything, just reasonably fit) and do not suffer from agoraphobia, meaning that I can wander around as much as I like. However, since wandering around completely alone is not a very pleasant and meaningful activity, and my life is empty of things to do, I spend most of my time in the house. Oh, and I am also not living on my own. I don't know if this is a severe form of SP, but I would say it is fairly bad.
I used to be extremely versed in mathematics and physics as a child, I remember making mental calculations much more quickly and easily than any other kid in my class, even those who were supposed to be "the best in the class". I could also understand rather complex concepts relating to physics, that some people find it hard to grasp even as adults. But these abilities sort of dried up with time as grew up, and I am now just an average person. It is very strange, but it was like this.
As for the meaning of IQ tests, I think they can be good indicators of certain abilities of the brain. Nothing more but nothing less. Certainly a large part of our brains' functions, especially those that consist of repetition of complex but learned schemes, are not easily captured by an IQ test. But nonetheless, there are good chances I think that a person who scores high will be one that is judged "clever" by most people who see him in everyday life.