Recognize that your fear of speaking is natural. You are not weird, you are normal.
Admit to yourself that avoiding the speaker's platform diminishes you. You can't stand out in a competitive environment if you won't stand up and speak.
Ask yourself, "What is the right thing to do?" Then take action and put the fear of speaking behind you.
"Put off till tomorrow." Take action today.
Take solace in the thought that you are an introvert or a "behind-the-scenes person." That has nothing to do with being able to speak.
Try to get out of it when the opportunity to speak presents itself.