Firstly, wow, I couldn't have worded any of that better than you just did. I can relate with a number of things you mentioned in your post. 1. I feel like I am being tolerated by my friends, but not actually accepted, and liked as their friend, 2. I can't stand conversations over the telephone, and I can relate 100% with the anxiety you feel in your stomach and around your heart, while feeling the phobia of the talking on the telephone in your mind, and 3. I remember experiencing in the past extreme self-consciousness about how I appealed to my friends while being out with them. This was especially the case when I was younger because I had a lot more friends then than I do now. Back then I was more extrovert than I am now.
I think you respect yourself a lot more than you give yourself credit for. If you are out with friends and you are just talking about irrelevant stuff all night, of course stupid things are gonna be said, and you are going to think back to them, and feel more self-conscious about them. If you don't find a coat to be nice, then why should you have to lie about it? You don't necessarily have to say that the coat is beautiful or anything, but you could comment on it some other way if your friend asked you your opinion on it, or if you noticed it from the beginning of the night and felt it was necessary to say something about it. You could say something like .... "Nice coat, where'd you buy it at?" Notice you cover all bases in one small sentence here. You let your friend know you like the coat, but then you steer the conversation and the focus away from what you really think in your head by asking a question immediately after "...where'd you buy it at?" Just be casual, state your compliment briefly, and change the topic.
As for pondering over thoughts about how the night went when you were out afterward, I know just how annoying that can be. You need to come to the realization that no one cares. When it comes right down to it no one gives a hoot what you said, or how you said it. Your friends know that you are just being you, and they will respect that you are your own person, if they can't respect what your personality is inside of you, then they are the one's with bigger issues. You wouldn't believe how relieving it is when your mind comes to the realization that no one cares as much as you think they do, and that you don't have to please the world are you to be happy. It took me forever to break free from my co-dependency, but when I did, I learned to be a lot more independent of myself.
Social anxiety is not for introverts only, it can be for extroverts, and anyone in between. In your case it is with strangers, and people over telephone conversations. Instead of looking at that as a problem, I would look at it as normal. In what sense should conversing over a telephone be normal? You can't see the person you're talking with, all you hear is their voice, apart from them laughing or whatever you can't tell what facial expression they have on their face, and you feel like you have to sit or stand in one spot while talking unless you are using a cell phone. Telephone conversations are not comfortable for many people, and there are a lot of reasons why. It is not necessarily a phobia, it could simply just not be a comfortable thing to do, or your personal way of communication with people. You will however get more comfortable with the telephone once you come to terms more with your social anxiety.
I am personally not an extrovert, I can't make small talk at all, and I rarely ever hang out with groups of people anymore. I also never feel energized after hanging out with a group of people, instead I feel drained. However, when I need to be social, I can be social. But only when the time is necessary, otherwise, I just keep my mouth shut.