I'm taking therapy and getting positive results, but the anxiety is still crippling me. How do I work past that, especially for public speaking?

I'm taking therapy and getting positive results, but the anxiety is still crippling me. How do I work past that, especially for public speaking? Around two months ago, I started speech therapy. Some people here say it didn't help for them, but it's working pretty well for me, thankfully. I'm learning how to control my speech rate, how to work easily through a block, everything. And I can speak pretty fluently too in relaxed situations. But all of that goes right out the window when I have any sort of public speaking. And not just presenting, but if too many people have their attention on me and it's a formal situation, I get the worst anxiety ever. My heart starts pounding so fast and the muscles in the mouth and face refuse to work properly. My voice sounds shaky and I block on every other word almost. How the hell do I work past this anxiety? I had an oral presentation in a Spanish class a few days ago, and barely spoke, resulting in a lower grade, even though I knew what to say. Now I have a history debate tomorrow, and I'm so scared of screwing up my speaking. I'm tired of suffering because of my stutter. It's the anxiety that prevents me from being fluent in these situations.