Public speaking is challenging to many at first. But here is the blunt truth: do what you fear most, and you will control fear, right? I know that you are probably delivering your presentation as I am writing this response, but just know that there are many, many ways to go around that fear (which is quite natural, by the way), even before you go out there to speak.
If the topic is not too new to you, you will be able to find ways to improvise intelligently when you forget that exact amazing phrase you were planning to shoot out there. But most importantly, with a newer topic, or anytime you feel you are losing it, realize that you need to practice your presentations. You can get your awesome self it in front of your mirror dressed the exact way you will be dressed during the event. You can run up and down a flight of stairs at least ten times and then do your presentation with a microphone in front of you to listen afterwards. You can also ask a small circle of family/friends to sit around and listen to you. It is called rehearsal time. Nothing shameful about it. But yes, you need to make time and put the effort into it. You may need to do it several times. The reason why these techniques are good is because they make your heart race and you will become just as critical of yourself as you will in front of your real audience.
I've learned these approaches from a great coach who wrote "Audition Success". I was a performing musician for a long time, read the book and did what he taught. Trust me, it helps. The presentation itself is nothing. The preparation is what counts. Writing the powerpoint is just the basic work. But your delivery is what makes the presentation powerful.
Do your homework. Rehearse. I know it may feel like a hassle, but how much do you want to improve, how much control do you want to have over yourself, and how confident do you want to be? As you gin more experience, you will need less rehearsing. But you may have some very important speeches in your career, when you will need many rehearsals again. Realize that very few people are naturally good public speakers. Very, very few. Therefore, set yourself up for success by creating the stress artificially in your home first.