phycis is a part of life ~

in physic ~ stress ~ is the ratio of the outside applied force, which tends cause a distortionm to the area over which the force acts... ==
but now i feel stress~ like the outside applied force ( final exam,test , coursework marks) ~ but when i using the formula to calculate my "stress"~ the answer is MATH ERROR~why??????

using the formula:
stress = applied force / area over which the force acts