Cheers in advance!
Experience. Nobody who talks in front of people a lot has not horribly bombed. It is almost a right of passage. After you bomb a few times and realize you are still alive, the fear of bombing gets turned down a little.
Preparation. Preparation builds confidence. When you are prepared, (1) you are confident, and (2) your body knows what to do even if your mind goes blank. When you are well prepared you only need to get yourself into the groove / pattern that you established in your prep, and your reflexes will handle the rest.
Mindfulness. The daily practice of being able to control your thoughts and emotions, exist in the moment, etc helps a lot when things get intense.
If you don’t feel some nerves in a big moment then you are not alive. Embrace it, be in the moment, trust your preparation, get to your spot / groove, and then let your preparation take over and do the rest.
You can get therapy but it will come down to exposing yourself to stressful situations so you gradually desensitize yourself. I experienced stress learning to play poker at real games, but the more I played the less I felt stressed about it.
For example, go to as many chess tournaments as you can.
In this statement in your question, is the answer to your question(!)
Basically you've answered your own question by your question (I love when that happens as a result of writing -- I've seen this effect numerous times in my own writing!) -- if you can recognize it!
Let me elaborate!
You see, the difference between any (so called!) stressful life event -- and a game (something played for pleasure and amusement!) -- is only really that you've got something to lose, something at stake -- in the (so called!) stressful life event -- which doesn't exist (or you don't care about) -- in the game!
In other words, you've created your own stress -- by saying/believing that "If I don't do X, I won't get Y..." where X is what you have to do during the allegedly "stressful" event -- and Y is what you won't get if you don't do X absolutely effectively, such that you succeed/overcome the challenge/pass the test/make the grade/do what's necessary/earn Y -- as a result of your actions, etc., etc.
Question: How would you play the game, er, "go through the stressful experience" -- if nothing, and I mean, absolutely nothing -- was at stake?
?
How would your mind react to that visualization?
?
If nothing were truly at stake -- then why would it matter if you did well or did poorly, or decided to do something totally lateral, like jump around and act like a grade-A buffoon? (I'm thinking of Jim Carrey here -- always socially inappropos in most of the movie scenes he is in -- but horrendously, horrendously funny! You see, here's the problem in a nutshell: You actually care!!! In other words, psychologically, you could be seen as what's called "high in conscientiousness" (a good thing -- a very good thing -- all top performers in various fields, including Elon Musk and many programmers -- could be said to be "high in conscientiousness". (I consider myself "high in conscientiousness", FYI...)) The problem is, high in conscientiousness -- while it's a common hallmark among overachievers -- also causes stress ! That's because, again, you actually care!!! You care about the outcome! Now, there's a lot of people in this world -- who don't care about things, who need to be told to care more (about themselves, others, the environment, etc., etc.) You my friend, would do well to care less! At least, just a little bit less! At least, just a little bit less -- such that the stress can be controlled -- or at least mitigated! You see, when all or most of the stress is gone, what remains is a game -- what remains is something called "State Of Play" -- that is, you've let go of all or most of your social conditioning -- such that you can enjoy, yes, actually enjoy -- being in that once threatening, once stressful, "high-pressure" situation! Think about it like this -- if the actual high pressure life situation was gone -- and you were an actor on a stage, and there were a bunch of actors, all of whom are acting that the stressful situation is real (a stressful test or whatever) -- but you know that it's not real -- that everybody is your friend and a fellow actor -- and that this is just Improv -- then how would you ACT -- under those conditions? ? This is what you have to train your mind to do... Freed of concerns about stakes (note that this will not happen overnight -- it takes some mind work to first identify the stakes, and then secondly, to drill the mind to basically "let go" of thinking about them, being attached to them, being attached to specific outcomes!) -- that you might actually enjoy "stressful" situations -- in the future! Anyway, wishing you a lot of luck! Know that all highly conscientous high achievers in the world -- are also like you! Also -- you might want to take in Improv class! You know, have your fellow Improv actors act out a stressful scene in your life -- but now you can be totally spontaneous, because there is nothing at stake -- What do you do? How would you ACT then? And might that experience be, I daresay, actually FUN ? ???