Is this way of coping bad? Please help, 10 points!?

When i'm at school, my friends can be horrible (happens at all single sex girls schools) and it really gets to me, the things they do. Don't tell me to get new friends, that's not what I'm looking for. Anyway, sometimes I feel like I'm about to cry, and when I do, you can reallly really tell. The only way I can stop without looking up is to pinch myself really really hard or scratch myself with my compass till I bleed or until the pain of the cut is the only thing I can concentrate on. It's not like, real self harm, but it can leave me with scars. But I'd rather do it than cry in class!! What can i do?? Is this bad? It's only in situations where it's public and I can't get out. At home I write songs and cry and then I feel better. But at school I have to hurt more to forget why I need to cry!! Plz help, 10 points!