Fear of public speaking is fairly common and quite treatable. It’s considered a social anxiety disorder, which causes people to feel so worried about being judged and embarrassed in social situations that they avoid them altogether. Stage fright, which is what you are describing, is specifically the fear of speaking in front of an audience because you imagine them having negative thoughts about your performance or you as a person.
The good news is that you can overcome the anxiety. First, try doing relaxation techniques 10 minutes before getting up in front of a crowd, such as deep breathing or yoga; that should calm you down. You can also try writing down exactly what you fear and think might happen. Then challenge the scenario: Is it really likely that everyone in the room will laugh when you open your mouth? And even if they did, so what? (Therapists call this exercise “cognitive restructuring.”)
Another treatment strategy is exposure—simply doing what you’re scared of so often that you become desensitized to the fear of it. Since it can be hard to find many opportunities to speak publicly, a number of psychiatric clinics have virtual reality simulators that allow patients to practice in front of a virtual audience.
In some cases, it’s necessary to decrease your body’s stress response to your fear. Ask your doctor whether you might benefit from a beta-blocker medication; this type of drug helps keep your blood pressure low and your pulse slow, which often makes your body—and in turn your mind— feel calm. If you go this route, road-test the medication to see how well you tolerate it before using it prior to an important public affair. Some people have low blood pressure normally, and taking a beta-blocker causes them to faint.