If you are feeling very anxious about delivering a speech, the most effective response is to:

Dealing with speech anxiety must be done before and on the day of the speech. Days before the speech, begin by identifying the reason for nervousness. By doing this you would be able to pinpoint specific things to work on.Practicing is also will help reduce nervousness especially if the main reason for your anxiety is forgetting the words of your speech. It is best to practice delivering your speech around 7-10 times before the day of the presentation.
On the day of the speech, exercise will help reduce stress and anxiety. Next, pick clothes that make you feel confident, this would help you hide your nervousness from your audience. Last find ways to hide your anxiety, if your mouth goes dry make sure to bring water or if your hands shake, make gestures to mask the shaking.