I don't know. I like to believe I will never give up despite the rejections and "derailed" life path. Best I can tell you is that it won't be productive to sulk over the missed opportunities whenever you encounter disappointment. I tend to do it myself from time to time, but know it to be wrong. Evidently, you are a bright mind with a bright future. How glorious would your eventual achievements turn out having been achieved despite stuttering, no giving up no surrender? How profound the gratification? As it stands, you may not be able to reduce it at will, but your spirit will harden with every time you keep walking in spite of disappointment. You reach a baseline where you doubt none of your worth and that's when you ace the test in front of you.