This, too, shall pass...
As I remember, it helped me to run various "what if" scenarios through my mind during alone quiet time. If my mind has familiarized itself beforehand with what concealed carry is and how it might affect my actions, any nervousness is greatly reduced... It's sort of like making sure I memorize my lines REALLY good if I'm acting in a play... That's the main thing and everything else just flows pretty easily... Like, I'm not going to be WAY surprised by anything. Of course, each possible SD situation is unique but they all have some basic themes. If I know those basic themes... no worries.
Reading books and articles about carrying didn't hurt me either.
I, too, feel MUCH MORE RELAXED carrying than not carrying.