Two days of tiredness

I have to conduct a two day course on Electric Drives this week. Today was the first day. I gave a lecture and conducted some class activities to about 150 students all by myself from 9 am right up to 4.30 pm. The only break I had was for lunch from 12 to 2 pm. Standing and talking for almost 6 hours has me aching all over and I also have a sore throat. I've got another full day of lectures tomorrow. I wonder how other people do it. I think I'll stop now. My eyes are starting to close. Night night.