Lets talk quantum. I have never across a physics arena so vague and interesting as quantum mechanics yet it is the only theory that can explain our universe so perfectly. Lets talk about Werner Heisenberg who stated that 'It is impossible to determine the position and velocity of a particle simultaneously with certainity'. You will have to sacrifice one for the other but not both. In other words 'It is impossible to be completely certain'. No doubt, restating the theory makes it seem less like physics and more like reality because it is.
You start a project, you have to deal with the uncertainty of whether it will deliver or not, we go through tests unsure of whether or not we'll pass, most important of all we are faced with the uncertainity of whether or not we'll live to face the next day. No matter who we are, we cant help but deal with uncertainity. Sometimes it comes in the form of impostor syndrome, sometimes in the form of fear, sometimes it is simply not coated at all.
You think you are alone in this but you are not. Not even Albert Einstein was sure he would change the world. For 2 good years he had to deal with the uncertainty
Richard Feynman, who by the way came up with some quantum theories, once wrote, "I think I can safely say that nobody understands quantum mechanics" .He was wrong, well, sort of. Quantum mechanics is just the reality we choose to ignore because a lot of noise comes disguised as reality. Uncertainity shows up the moment we enter planet earth, is it a reason to stop us from reaching our potential? No, it is actually a reason to strive on since that's how life becomes amazing. In short, whatever you do, you will either pass or fail but do it anyway.