Thank heavens we are not robots and unfortunately we have body parts that are not always in A one shape, even if we take excellent care of the body. With the body's adjustment to a change of climate which REALLY occurs April, May, and June, it is possible to not feel up to par. To answer this question, modify the "meat" of what you are saying and be sparkling for the introduction and don't apologize for being a human! Hints for the introduction:are to memorize that sparkling smile and the first sentence you say. Now you are considering how to comfort yourself during the presentation. Some possibilities are to have that favorite herbal tea if it is sinus related since it is very warm; have that fizzy SUGAR FREE carbonated water which can be very bubbly if your stomach is upset; have that flavored water if a joint hurts. Every time you take a sip, mentally say "I am helping these folk here in some way; I am average; with every sip I am getting closer to the end of this presentation."