I sympathize with you completely and totally understand how difficult it is
not to internalize any comments that you might receive from a parent.
Whenever I'm confronted by a parent I spend days thinking about the
conversation and playing it over and over in my head. Eventually I find the
need to enter the "zone" which is basically a place that I go and pull out
my pencils and paper and just start drawing or painting. It really relaxes
me and keeps me from thinking about what happen. Or I clean... cleaning is
very therapeutic. You might try and do something like that to ease your
mind away from your parent/teacher conference. Just an idea.