Well, I used to be. I would start to sweat and talk really low and I wouldn't know what to do with my hands and then to make matters worse the teacher would tell me to speak up which would make me even more of wreck.
In college I took a speech class and it really taught me a lot. Just about every week we had to do a speech presentation sometimes in groups and other times solo.
It really helped a lot to be honest. Making eye contact with a whole room was scary a hell and you feel like people are judging you blah, blah, but the key is to focus on yourself and put those thoughts in the back of your mind. Breathe and stand up straight and the most important thing is to project your voice. It's easier said than done though. You could also practice in front a people as well too, I still get nervous here and there but not like I used too. The more you do it the better though.
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Not me giving a whole lesson though.