Suggest please

i am so depressed these days.i know i have to study,but couldnt do.i am so average student.i dont understand at once.neither i have courage to ask teacher to tell it again.i understand so late..i dont know how to read conceptually .i passed my foundation .i really want your help how to understand conceptually?evyone says to  study conceptually but i have no idea how people do.i forget things so fast.i need to recall so may times.plz do  help me