It looks as though the Blumpz Signal is in the night sky. This is a real complex problem. One that involves many drugs, a failed support system in her immediate life (drug dealer boyfirend) and what appears to be a series of clearly overwhelming emotions that are manifesting in damaging thoughts and behaviors. Is she addicted? The addicts i deal with have no clue that their drug use impacts so many. Is your friend an addict? Just the term addict can change one's perception. Whatever is going on in her head is beyond anything i can attemp to diagnose in a post, but she clearly hates herself and life because of this hate. To escape herself could be one of many underlying mechanisms. She needs help.
Be careful attempting to reason with the unreasonable. Make sure to not attack but clearly emphasize that you understand (the phrase "this is what I am hearing you say"). The reality is that an intervention is only effective for people that realize they are an addict. Reiterate to them that who they were before addiction was so much more functional and healthy and everything changed after addiction. Establish clearly understood boundaries with consequences and stick to them with everyone that is there for the intervention.
Your friend can react in many different ways to the intervention (guilt, anger, denial, fear, silence, vengeance among many more thoughts/feelings). Whatever she is doing is not working...and you cannot be afraid of losing your friendship because it sounds as though the friendship is already lost at the moment. Be strong and patient, but it is okay to let go after you feel you have done everything you could.
