Basically my best friend use to be amazing and I really looked up to her. Well a yr and a half ago she moved to MD and began doing heroin . Everything has been downhill since. Her parents had to take custody of her daughter, and she's been in and out of rehabs. 

Lately she seemed to be doing better and came to visit me with her daughter last week. Welp, I dropped my 8 yr old at school like usual and came back to find her  5 yr old trying to make breakfast and her in my 8yr olds bathroom shooting up. I also have a 5 month old, so she was in the vicinity of all this as well. I just shut the door, and went to make her daughter breakfast. I was in shock I guess , I then called her mom to come get her daughter bc I'll be damn if she drove anywhere with her. After her mom got her daughter, I just told her to leave as well. When she left, I go binto my daughters bathroom to find she had just thrown the needle in the trash 😡. Ithinking about it makes me shake. That she would bring it around my daughters and even her own ! Well I have yet to actually talk to her but she's been blowing my phone up saying how horrible of a friend I am. Was I wrong? Or harsh? What should I have done ? What should I do?