Funnily enough I'm a corporate communications/PR manager who handles external and internal communications and has to regularly speak to senior executives/the CEO and handle large media events. I always had a chip on my shoulder regarding speech and doing this was my way of saying fuck it, I can do it. I still block a hell of a lot, but just keep going. There are bad days but it gets easier to shrug them off after you've built up enough experience to know it does not determine what people think of you or what you're capable of.