Presentations make me so nervous that...?

Here is my story. I remember one day in college I was to give a presentation. I was well prepared. Note cards in hand and well rehearsed I headed to the podium. At the podium I took a quick glance at my first card and began my opening. Then the strangest thing happened. My nerves deserted me. My sight began to get blurry. The sound of the room and my own voice went silent. The feeling of any movement, numb. Next thing I remember was coming to. Seeing that I was holding one last card. Making a closing statement and the cl applauding me. To this day I have no idea what happened between the first card and the last. Today, decades later, I am an instructor / trainer and give a dozen presentation a month. What I did was to accept it for what it was. Not to worry. And move on.