We all get over reactions from time to time. Figure out where you overreact and analyze it. Establish a plan for dealing with emotions when you have time rather than in the heat of the moment. This is true in sports, school, work, relationships…
During practice, before practice, after practice
Same for a game or race or event…
What emotions come up for you that get in your way?
What thoughts are going through your head that interfere with a better performance?
Continue thinking about these distractions and what you would prefer to focus on (results, tasks, process) and figure it out.
How will you deal with these triggers?
Do you want your emotions to control you or do you want freedom?
You have control over that part of your performance and can instantly improve your performance, simply by doing that.
If something from outside of school or the sport is distracting you, consider talking with your parents or a profession or both to help you manage it.