Relax, we all know how you feel. I once prepared myself to presentation with another person, I made that presentation, knew word by word what to say, rehearsed it many times, learned by heart, and that other person was like a free rider, never saw the presentation other than 2,5 min before we present it. Yet I completely lost it, suddenly I didn't remember what to say, stuttered, a lot than usual, while he just presented the topic as if he knew what he was talking about, the sentences came out from his mouth smoothly without hums and ahs. This happened to many times, each time I was very very envy of how my peers could just give speech with such ease as they do. I could give an arm and leg to speak like them. But at the end I started to give up, and from there I became less anxious, thus my stutter becoming more moderate (normal stage) when presenting. So don't be cruel on yourself. ​ P.S sorry for my English.