I never really disliked the class, in my MBA classes the profs often talked about having a "sales" gene. Some people have it, others don't. It's nothing you have control over, but it something that you either like doing or don't. I like selling people products (not hoodwinking into deals, but explaining features and benefits).
Look at public speaking this way:
1) Know what you are talking about.
2) Know every single person in that audience is in the palm of your hand and hangs on ever word you have and cultivate that power into something you can control and manipulate into proving your point ("selling").
3) Prove what you are talking about in a concise way to keep the audience's interest and,
4) You will be seen as god in the class if you don't seem stage shy or worried about how you come off. Think of politicians. Do you think that they always want to get on stage and be "on" 100% of the time? Probably not, it's all an act. Whether you are performing Shakespeare or giving a speech on Japanese Supply Chain Philosophy, know your audience and keep them on the edge of their seat...
Good luck!