What do i tell her help

Ok so recently my sister got in trouble for having sex in my paraqnts house and shes only 15 but shes been having sex since she was 13.But i got tired of her having sex and hearing the noises and i would always cry after words cause i hate to see my sister to grow up the way shes growing up.I prayed one day for my sister to get caught and when my dad came home something gave me the confidence to tell my dad so i just told my dad my sister snuck a guy in the house again.Now for the past 2 weeks she has been crying over him cause myparants say she is grounded for 2 months and the dude doesnt want a in school relation ship only shes having suicide thoughts and im gettting scared.Today she was telling me the little moments mattered the most and it made me sad i started crying cause it made me feel so bad for what i have done its just i couldnt take it anymore. My sister loved this guy and i rewined her life and if she kills her self its all my fault and i cry every time i think about the bad thing i did i think i should of just let her have her fun.
the good thing that happened is that she doesnt yell as much and she doesnt put me down as much either
I have 2 questions am i a bad person for doing what i have done and what should i tell my sister to help her get threw this(and she doesnt know im the one who snitched