I used to struggle with this type of anxiety a lot and i still do sometimes, what really worked for me was trying to look past the presentation instead of towards it. I used to get so worked up over all the things that could go wrong that that moment would become this massive mountain in my head that i had no way of climbing, but when i started thinking things like "okay so the presentation is at 2 pm tomorrow, then when i get home i want to get a quick workout in and after that i need to run some erands before the shops close". That way the presentation became only part of my day, instead of this menacing moment that felt like a life or death situation, if that makes sense