Go cry us a river. Somewhere along the line SHE made the decision to start taking drugs. Somewhere along that road SHE decided to start taking heroin. She died as a result of her decisions.
I'm sorry that this hits close to home for you due to your own addictions. You need to look beyond the commonality that you have; look at what makes you different. You acknowledge that you have/had an addiction and have done something about it. You mention above that you went to a meeting last night, which is a decision the YOU made. She repeatedly refused to go to rehab and continually went back to her heroin addicted boyfriend, despite what her family's attempts.
I've lost friends due to their bad decisions too, we all have. Some have been very close friends doing activities that we do or did without realizing that we were making bad decisions.
People who die of their own hand, which an OD exemplifies, made their decisions. In a case with a long-term addiction like she had, it was a decision she made a long time ago and never tried to remedy. It's like committing suicide in slow motion - a perpetual f* you to everyone who has ever loved or cared about you.
Oh, and if you feel like judging us for how we react to the death (suicide) of this individual go for it. But do you hear anybody judging you for your addiction? I haven't.
Get over it, because you aren't her and she isn't you. You've made the hard decision to get off that deadly path.