I feel like a bad friend

My best friend is only fourteen and I'm the same age as her but I'm 9 months older. Anyway, she just told me that she was pregnant and that she had sex because she thought she was ready. I calmly told her that she should have used birth control but I'd be there for her no matter what. Then she told me that she knew I was going to lash out on her like that and she was actually raped. Did I really do anything wrong? I feel terrible for her and I want to find that guy and kill him and wipe away her tears and hug her a lot but I just don't see what I did wrong here.