I don't endorse people 'white-knuckling' their way through meetings. Also, I don't endorse people leaving in the middle of a meeting - it reinforces the escape and avoidance.
After going to my first NA meeting, I actually felt like smoking cigarettes and weed.... it was that stressful. When it gets to that point I think there are diminishing returns.
Take baby steps if need be. Ask someone to go with you. Or when you are relaxed and calm, close your eyes, and imagine thru imagery a positive experience at a meeting.