Within a week, you were riding the bike. Presenting or speaking is the same as riding a bike. The more you do it, the more you know how to do it, and, over time, the more you know why you do it, and the more confident you become. Dwell on the past victories and successes. Remind yourself of when you did it, not when you didn't.
Many people have fear and are clueless as to the cause.
Sometimes that self-discovery is enough to make it dissipate or disappear. Please note that I have already given you the supreme confidence-building answer. It is contained in The Strangest Secret, and I recommend you listen to it once a week for a year, then once a month for a lifetime. I have, and so far it's working. Earliest info on new businesses, homeowners Sales Prospecting Center Real info, real opportunities.