Stress/pressure has an effect on your performance for sure. In high school I didn't have many problems but at University I found I would often choke during exam

Stress/pressure has an effect on your performance for sure. In high school I didn't have many problems but at University I found I would often choke during exams despite knowing the material and being well prepared. I would get extremely nervous in the lead up to my university exams, I'd have difficulty falling asleep the night before, I'd be tossing and turning all night going over everything in my head and I'd feel anxious and sick (my stomach would be incredibly queasy) to the point I'd have trouble eating anything in the morning. So I'd go into my exams tired and irritable (because I hadn't eaten much) and I'd make stupid mistakes. Eventually I got over this but it took me a year or two and it definitely had an effect on my grades.