As I was walking I felt God bring to mind the verse in Isaiah 26.3:
"You will keep in perfect peace all who trust in you, all whose thoughts are fixed on you!"
And immediately grasped hold of these two things:
1. My marks were not going to change based on whether or not I worried
2. The ultimate end was not whether or not I got the grades I desired, it was God's plan, which would be realised regardless of my grades.
And so, as I focused my mind on Him, I found myself in perfect peace, isn't He great?