I am a complete introvert and was more fearful of public speaking than probably anyone you know. That's why I joined toastmasters which was supremely challenging at first, but through repeated desensitization (i.e., practice) you become less fearful. Public speaking is still not my favorite thing, but at least it is not limiting my personal and professional growth. I can now give talks at conferences without having a complete panic attack. There are other benefits too like practicing your extemporaneous speaking skills (table topics for you TMs out there) such that you sound cogent even when someone catches you off guard.