Frustration?!

OK, what do you do with this kind of conversation?
"I"m frustrated"
"Oh, why?"
long conversation getting no where....then...
"I studied 3 hours for my history test and just got a 97%, I wanted 99%"
Am I over reacting if I feel like banging my head against the wall?
Yes, I know the spelling test was a disappointment...spent a lot of time
learning the vocab words,but neglected to study the spelling
words...maybe because they were just...flowers? 81% oh that is a "C" !!
I know that in his head he is equating his value/worth with getting good
grades, even though we try not to emphasize the grades at this house.
Guess tonite he just had to check once more if he is still valuable.
I told him I will love him even if he gets straight "F's" He didn't
believe me...wonder if he will try it?