You can do something about this. I also was/am a full stop blocker. Teacher calls on you. Either say nothing or say “pass”. Or just say “no”. It’s your life, you can do whatever you want. If you don’t want to do a presentation, goddamit, don’t do it! They cannot force you to do anything. I got thru high school not having to do any speaking at all. Be mentally tougher than they are. They aren’t going to fail a speech disabled kid.