Your nervousness in public speaking is merely the by product of some deeper seeded fear you have. Most people are not aware of this, but oftentimes when you experience nervousness before speaking in public it is just your body's fight or flight response to the situation. On some level you're feeling like this is a life or death situation, get over the feeling of this being life and death and you'll ease some of the nervousness you feel before a public speaking function, but if your nervousness is severe it may be full blown anxiety as supposed to just nervousness or a simple fear.
Understand that severe nervousness when it comes to public speaking can be classified as a phobia known as Glossophobia. Glossophobia is an extreme case of anxiety that comes with the fear of speaking in public, the symptoms include heavy breathing and a rushed heart beat that feels like it's going to beat out of your chess. Your nervousness may not be this severe, but it can definitely become this severe if you don't take measures to get it under control now before it has the chance to progress into the more serious form.
Luckily for you there is a group dedicated to helping people master the art of public speaking and overcoming their fears as it concerns this, the group is called Toastmasters. Toastmasters is an organization that's been around since 1924, they help people gain skills and confidence as it concerns public speaking. You may want to consider joining this organization as it could serve to help you get over a lot of the fear you might have about public speaking. You can join and find a meeting place near you for your convenience.
Using medications may also serve you well in helping you to overcome your nervousness when it comes to speaking in public. Your body is set up to protect you from certain situations where it feels like death is a possibility. You have internal mechanisms in you called beta adrenergic receptors which are activated by certain types of chemicals released by the brain, when these chemicals are released they cause intense anxiety related feelings and symptoms like sweating and fast heart beating. Taking a beta blocker drug helps to stop this rush of chemicals there fore controlling your nervousness.
Overcoming your nervousness when it comes to public speaking is easy once you decide to take the appropriate action to do so. Taking a beta blocker to block some of the chemicals released by the brain can help control these feelings of anxiety.
Joining organizations like Toastmasters can help you master the art of public speaking and give you unstoppable confidence, and knowing how to identify whether or not you have Glossophobia which is the term used for extreme cases of public speaking anxiety can all help you take control of this problem and speak in public with no fear. Take these methods seriously and you should be on your way.