Even accomplished speakers will have some fear when they are about to give a speech, so some anxiety is necessary to avoid a flat presentation.
What happens is that for novice speakers we let this take over.
Firstly I would ask you to get in touch with the emotion.
Say to yourself, “Right now I feel terrified, AND that’s OK!!!
Say a few times , even though it’s through gritted teeth.
What this process does is help you accept the emotion.
Based on what you deny, controls you.