@The-red-centaur, I don't know how to manage it, but, maybe you could make a list of questions that you think your going to be asked and work out how you will respond and prepare yourself a little that way.  Try and take a few deep breaths after each question and that should help compose yourself. 

Do you have some support to help you now and during the case?  Admire your courage for doing what you are.  Wishing you all the best with it.