Disappointed

ya, i was finished my first year exam!
of course, exam was finished is a very happy thing. I can relax, continue my hong kong drama or movie, keep maintain my sleeping time, and bla, bla, bla....
but i'm feel so unhappy, just don't know why?!
especially when i done my account paper and hand in...i really felt so sad and unhappy whole day because i had some questions was done it at random, and 1 more struktur question was blank it, i forgot the formula, OMG !!! I felt so angry why i will forgot this formula. It is very simple steps and easily for me to remember, why i will forgot ! AHHHHHHHHHHHH
I have waste so much of time in my account, i also burn the midnight oil in every subject since the exam started...but,,,haizzzzzzzzzzz

whatever, exam was passing through, actually i will feel so disappointed until now, but what can i do? I'm not doing well and enough in my revision, i just can admit and complain it. I should finish all revision before the exam coming, but so many things are seduction, i must try to control it.
SPM is coming soon, i need to control my mind, let it cool down and depart from the seduction.