You may want to discuss this with your doctor and look into beta blockers. Anxiety related specifically to performance issues can be overcome without the use of benzodiazepines. Lots of athletes, musicians, public speakers use beta blockers before an event.
Check this out:
http://www.ethanwiner.com/BetaBlox.html
While it's true beta blockers might help, you can also try to tackle this without meds. You can try a performance coach or a therapist. Lots of people with stage fright have long successful careers without ever completely getting over it, but they learn to use it in their favor through techniques such as visualization, meditation, and rehearsal. Whatever you try, good luck.