Study alone

Ahh.....finally i enter the University life..life is not as easy as i thought....everything went so fast,no more spoon feed,no more one on one guidance from teachers.....i am on my own now.Now that i discover i am slow learner...i have to study 10 times harder than my friends,especially subject that involve calculation.I really envy my friend,even they only study less than me but surprisingly they did well in class.Why is this happening?i thought those who study hard would perform well in exam..this why this does not happen to me?i study hard,i even make my own note but i still cant remember the note i had made.....i aiming for good result, i nearly give up..but the other side of me still constantly reminding myself "maybe is isn't time for u to shine yet...keep fighting,one day u will success!!" does anyone wan to give me a lift?(i really need a motivation)feel free to do so...thanks in advance ^^