If you feel your therapist is not helping you, then chances are, they aren't. Find someone else you connect with better.
Try to get to more sessions if you can, but I know that between the insurance companies and the economy, therapy has become more of a "luxury" than it should be!
While I hate to advocate drugs unless they are a "last resort," there are some good medications you can take on an "as needed" basis to help you relax. Perhaps you should discuss that option with your therapist. But you say you won't see him/her until after this talk you must give. Perhaps you could speak with your PCP about this and talk about a VERY mild antianxiety med to use before your talk. IF they do give you something, do yourself a huge favor and try it out at home to see how it affects you. It's bad enough that you fear peeing your pants in front of a crowd, you don't want to do it while you lay snoring on the floor!
I would ask my therapist if he/she has group therapy for this issue. Perhaps that might help you take some "baby steps" in getting over your social anxiety? Just a thought..............
There aren't many of us who actually enjoy speaking in front of groups, but the times I've had to do, one of the things that helps me is to be absolutely, totally ,100% prepared and comfortable about the subject I'm presenting. If there is going to be a Q & A at the end, think of every single question that could possibly be asked and prepare your answer ahead of time.
I think you'll do great. Practice your CBT as much as you can. Try to talk to small groups of friends for practice and ask for their support and suggestions.
There are some good books available on this subject.........you might benifit from reading those.........get some good ideas on how to relax.
Eat a good meal with protien beforehand, but a light meal. Do not drink any alcohol to help you relax. Big mistake, that! Wear clothes you are comfortable in. Have your talk outlined in a manner that is good for you so you don't get lost.........I used note cards with each "point" I needed/wanted to make written at the top and then a few reminders of what I wanted to say about those points..........written in LARGE letters so they just "popped" out.
These are some of the suggestions I found in a book on public speaking and they helped me. I was still scared, but I felt really prepared and that helped more than I thought it would. It's when you fear your thoughts are just going to turn into total chaos and you'll look like a fool...........that is such a huge part of the problem. But there are many things you can do to help get you through this.
Pretty soon you'll be carting around your soap box.............they won't be able to shut you up! LOL
Peace
Greenlydia