friends?

what is a thing that called 'friends' ??? ,do they hide when we have some problems? i think that isn't. i just want to share about my feeling now. i'm so sad now, my friends are change in grade8 . one of them now like an enemy with me . i don't know what must i do for change that likes formerly ??! , please tell me how the step to change it !! i miss my old friend so much :( , but they don't know it, now i just able to be a more patient person :')