I am super outgoing IF I am comfortable around a group of people. However, when I am around new people or people that I have very little in common with, I too get really insecure and almost introverted. I spent years trying to build friendships with people that really didn't get me, it was a lesson in absolute futility. I found I just got more insecure and withdrawn over the years.
I did finally find a group of people who, too my surprise share a great deal of my interests (and not one of them watches "reality tv"
). I am much more outgoing overall, even with new people now. I'm not the smartest of the group, I'm still very overweight, but I now have friends who want me to be around. I'm convinced this make all the difference in the world. Don't keep banging your head against a wall, by continuing to look for friends in the same old places, if need be start looking in new places and keep looking until you find them. You'd be amassed what that can do to your self confidence.
As far as dating and finding your match - sorry, got nothing.