Here is something i read to increase confidence levels, its worth a try:
STEP 1 - Think back to a time when you felt really, really
confident. Fully return to that experience in your mind and
body. Think of the feelings that came with that experience,
visualize what you saw, hear again what you heard, and feel now
what you felt then.
(If you can't remember ever being confident, imagine what it
must be like to be self-confident - to have all the strength,
power and self-belief you'll ever need.)
STEP 2 - Enjoy this memory as you experience it once again, and
make the the colours brighter and richer, the sounds more
lively and the feeling stronger.
STEP 3 - Sqeeze your thumb and middle finger together as you
relive these feelings.
STEP 4 - Repeat the first three steps several times with
different similiar positive memories until just squeezing your
thumb and middle finger together is enough to awaken this
feeling.
STEP 5 - Continue squeezing and think about a situation where
you want to feel more confident. See in your mind everything
going well, going perfectly - exactly the way you would like.
The next time you feel challenged by a situation, simply
squeeze your middle finger and thumb together, and these
feelings will return. It's not magic - it's just retraining
your mind.
The human brain is a complicated device, but it obeys simple
rules. When you feel more confident just imagining these
scenarios, you will feel more confident when they actually
occur.
This process should yield instant results, but if you repeat
these steps everyday this week you can forget worrying about
confidence and concentrate on your conversation!