I'v always had similiar experiences myself too like sometimes lately i have been trying to when the chance arises to talk or try to start a conversation, but it's like once i start thinking of something to say before i say it ,then it's going to come out in an unconfident forced way so i'm better saying nothing and try to look confident lol,
But having told them you have social anxiety must have eased ur anxiety a bit, sounds like a good way to go .