Need help with girlfriend and her addiction to H

[Wallst]

Hello all,
First of all, I'm a newcomer to this board and to this type of addiction as well. I myself, do not have any drug addictions and do not drink alcohol either. I been dating this girl now for 4 months . I knew her from high school and have not seen her in 20 years. After seeing her, we quickly began hitting it off and hanging out as much as possible. 2 months ago, things started to change. It all started with the loss of her job. She said she lost her job due to lay offs and that the company's business was slowing. This is where it all starts.
Not long after the lay off, she became sick one night and that night turned into 3 days of her going MIA on me. She gets back to me and tells me that she got really depressed and that she was in a lot of pain and that she used heroin. She said she had did it a long time ago and that she promised that she wouldn't do it again and that she was sorry for disappearing and she would understand if I didn't speak to her again.
Trying to shorten this without losing too much detail that may be important. So she starts going to hospital ER trying to get prescriptions for Percocet and Xanax. Come to find out that she's been doing that for years. Didn't know that she had a major problem. I really have feelings for this girl and told her that I'm not judging her, trying to control her or any of that. She said she never had a good guy as her boyfriend, and they were abusive and controlling. So here we are 4 months into this relationship and we have had some very rocky points. Just last weekend , we had breakfast on Saturday and then we were supposed to have dinner later on and a movie. I get a call at 4pm saying she can't make it , something came up and that was it. 4 days MIA. She texts me on the 4th dsy and says she misses me and wants to see me. Oh and if I have any Percs she could have ... I go on over and she was kissing me and says she realized how much she misses me when she doesn't see me this long. She then does something she really never did before. She admits to me , her use; shows me her injection sites, and says that she is thankful that I'm not judging her or making her feel like ****. She then asked for my help. That is exactly what I am going to do.
Here is what hurts. She recently found out that she has some liver damage and that she has fibroids. She is in a lot of pain with all that. We haven't been able to be intimate with all that going. Things have def changed and I really want her to get better. She said tonight that she goes MIA because heroin is not a social drug and that she does it alone and just stays home and not have me see her that way. She just wants me to to reassured that she doesn't wanna lose me. I'm scared and do have feeling for her. That is what is making this even more difficult. This weekend I wanted to take her out so we shall see how that goes. How do I know if she used again and just wondering if she will ever stop. I dont want her to run away so I dont want to question her or tell her she better stop or else.... I don't want to be that guy. She told me that she likes that I've been patient, she doesnt feel the need to hide from me, and that no guy would've stuck around , she thinks. So she wants to take it one day at a time. She is so beautiful too. I know she can do this. I will be supportive through it all. But is this doable? Please, any reasonable and reality , feedback will be helpful. Please!!!