[...] "she was my best friend and I loved her this whole time but you made her kill herself", [...].
No need to love her (romantically), if that's what you were implying. I'd be pissed if somebody drove one of my best friends to kill themselves. Look at it that way, it's probably somebody you knew years before, somebody you shared a lot of stuff with, maybe somebody who had helped you through tough times and then, a lover come out of nowhere and some times later, your best friend commit suicide because of this...
Well, we don't know the details, we don't know what happened and society tends to put love over friendship, but that still sucks ass in big time. Her enmity is largely understandable and justified, she could be a bit more forgiving, since this is a teenage girl in that case, and at the very least shouldn't put salt on these wounds, but emotions and stuff.