There's a lot of good advice in that, but some of it would be too regimented for me, and I've never been able to handle too many social activities in a short period of time.
> anyone with a reasonable amount of intelligence
...can talk themselves into feeling apprehensive about pretty much anything. Not advice for OP necessary, but getting out of your head is definitely advice many of us needed.
All this jazz about brain chemicals is just as much a distraction. Just another "intelligent excuse". It can be harder for you, and depression or other conditions can make things even harder, but buying into this intrinsic sense of this is what I am is what reenforces these traps.
Edit: You've since elaborated, but I'll let my original post stand. I agree with you much more now!