I'm an NT, but I share many of the same problems you've described. I used to be terribly shy, especially considering the business I'm in, where making contacts and chatting easily with people is crucial. When I did push myself to be more outgoing, I had difficulty knowing where the "sweet spot" was. I can't even
tell you how many times I'd review my behaviour, after engaging with a new person, and kick myself for being too eager, too polite, too--anything that wasn't what I intended. If I was talking with someone at a gathering and they excused themselves for any reason, I'd go
mad trying to figure out if I'd turned them off me. If I said something in a group and nobody responded straight away, or if nobody laughed when I said something I thought was fairly witty, I'd want to crawl under the nearest piece of furniture. I shouldn't use the past tense, really. It's still a problem for me, though getting older has helped be care about it slightly less.
And, YES, I even do similar things here on AC, especially since I'm in the NT minority. Sometimes the "karma" count is my worst enemy, because if the number doesn't move after I've made some posts, or
worse, if nobody responds to my comments or questions, I worry I'm not well-accepted, or that something I've said has come off as stupid, or way off-track. And there it all is, in writing. No take-backs! (Something about keeping a visible count of social approvals on an Aspie support forum seems counter-intuitive to me, sometimes.)
I wish I could tell you how to simply feel all right with yourself around new people, but I can't. What I
can do is tell you in giant letters:
YOU ARE NOT ALONE!!!!