How do you handle blockage?

How do you handle blockage? I have a conference coming up where 30/40 professionals in my field will be gathering for a 2-day event at a hotel. The agenda lists Introductions/Roundtable as the first item which involves introducing yourself for a couple of minutes. My problem is that I get severe blocks during introductions and one time I almost fainted. This is damn scary for me given I have to sit with these professionals for 2 days so I don't want to start with a pity party and awkwardness. Please please recommend me some ways to introduce myself without having a severe block.