Mark,
You show the classic signs of an agoraphobic. I also have difficulty at major events, but it's not because of the people....it's actually about feeling confined to a particular space. Have you ever tried sitting near an exit at these events and seeing if this helps? I'm normally like you, where I'm able to handle every day things, but in the past couple of months, my anxiety has crept up again and I've become nearly terrified of leaving my place. I definitely agree with Char...do your best to carry on as normal because if you don't, agoraphobia will overtake your life.
I just had an appointment with my therapist this week and she recommended I start out each morning with a walk, and then try pushing myself more and more to stay out of the house. I've found that Xanax really helps for the most difficult days. Also, Lexapro saved my life for several years in terms of anxiety, but recently stopped working for me. Perhaps an SSRI can help you, too? Good luck to you!
try your best to carry on as normal,dont just sit in the house,because if you do it gets so much harder to go back out again.get some help,go and see your doctor.when you feel yourself getting nervous just try and relax your body,try taking your mind of whatevers bothering you,and take some deep breaths in through your nose to the count of 5 and out through you mouth
hope ive helped in some way x