I can relate to almost everything there. It's horrible going over everything after the situations for x (long) amount of time, all the seemingly stupid comments. The final line is the most telling - for me at least - the lack of practice...
I can honestly say that the practice in whatever form does help. I was forced to do things I wasn't - and still am not - comfortable with, and this being practice, it does make things somewhat easier. I have fears of talking by phone and in public, of people hearing (the wrong?) things. My job forces me to call people now, even though for years I've avoided it and sent emails, now I'm actually good at it (even though I hate people nearby hearing me talk).
The other part, is somehow learning to not care as much about what others think of your actions or what you say. They also say the same shit and continue supposedly without regret or a second thought to all later. It's a good value to care about your parts in all, but difficult to hold it all there to analyze so much. Social anxieties are a bitch, in my recluse and basically stopping all the caring of others talking about me behind my back (they're not going to stop) and try to get on with things, it's attempting to rework my brain's thoughts and cycles to function and continue even if not to specifically cure the problem.
I hope you can find what works for you. Mine is learning to cope and getting the balance to get through each day. Alcohol works with social situations too, even if it's not the right way to do things.
Do not listen to a word I say
Just listen to what I can keep silent
The only way to gain approval
Is by exploiting the very thing that cheapens me