It’s called “choice paralysis” and what occurs is that your brain is working so fast & can go in so many directions that it feels that it just goes blank. It does not go blank. The thing to do is to take a breath & start talking. Just beginning to speak will kick you into gear and then you can find your way to the point you are trying to make.
When put in a stressful situation our instinct as humans is to take flight or stay & fight. Public speaking forces one into staying & fighting. Remember that the audience is not adversarial, they want a dynamic presenter. They are rooting for you to succeed.
Take these three steps before getting up to speak:
1. take two deep breaths to calm yourself
2. squeeze your hands together a few times to move the adrenaline through your body
3. be positive to yourself in your mind..work yourself up, not down.