If you fail at something you have to work double or triple what
people put in.
Classic example is my math for 'O' Levels. I'm always a F9 student
in math. I started studying math for my 'O's 6 months before the
exam. Forced myself to do all the questions in the text book and 10
year series, plus other assignment books.
In the end, I got a B3 for my 'O's for Math. 
No use complaining. You really need to put in the effort to succeed
