First you have to own what you have done, because you can't get that time back, go get some help with this situation - consoling. Second, you have to gather yourself around new people who don't know anything about this. If worst come to worst - move away from the situation and start your life over, by going to college in another town or state, and maybe share your experience with younger girls to show them that they don't have to do what you have done to fit in. I sense that you realized that you made a mistake, not your first and I know not your last, but it's a part of growing.