I've been having this happen more and more often. I get past it though, everybody screws up, so mucking up some words when talking about something doesn't matter. For example, I got subway for lunch today. I was asked what cheese I wanted. I replied cheese. Not what I intended to say. I took a second to regain my senses, did a quick mental reboot and continued as if it had never happened. Its not something to worry over.
As for not talking much, I'm much the same. Being quiet/holding your tongue is not a bad thing. As long as you talk when needed, its even seen by some as a good quality. Problem I have is that a lot of people expect me to talk a lot and be loud etc around them, because I always was. Its not who I am, but I force myself to adhere to it. Burns me out pretty quickly.
Have a nice day too, Strawberry.
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