Boy do I hear you. And your admitting that you don't like it when things don't go your way takes tons of courage. I don't just mean admitting it on-line, but to yourself. Huge!
When I became pregnant I felt so exposed. Everyone wanted to come up and talk to M. and I didn't want to have to make conversation with strangers about something that was so private to M..
When my daughter was born, even more so with the casual comments.
There is a difference between introversion and social phobia. I'm introverted. I love it, accept it, totally at peace with getting energy from being alone or with those I know VERY well. But then there's social anxiety which you describe a little bit (I've had that too but now to a lesser degree than when I was younger) and that is fearing judgment in a social situations to the point of avoidance. That's what you don't want to teach your son.
But, you're actually not doing that. You may not have friends that have children, but you are modeling having friendships.
I've gone out of my way to join groups through MOPS, meetup.com, yahoo.com, etc and though haven't stayed with the group (just not a group type person) have made one or two friends from each.
I have a wonderful friend from high school whose mom is my role model. She's introverted. She's also dynamic, warm, intellegent and an incredible listener. She gave M. the secret that although she considers herself shy, there is no reason not to be able to listen to others and ask others questions. Sometimes its as simple as thinking of questions ahead of time, role playing, in the mirror maybe, or watch others who are at ease in social situations. I've learned a lot just from watching. My personal motto and one I've used often when counseling others with social anxiety, "The most interesting topic, to most people, is themself."
I could go on and on about this topic because the past few years I've been working on this, still am to a large degree and getting better with practice, but it does take practice.