Why Does She Hate Herself So Much When I Love Her So Much?

I feel:: distressed

My girlfriend, E, came over to my house yesterday. She was carrying a 40oz Miller Lite when she walked in. It was only 12:00pm. She had already taken a bar of Xanax I found out a few minutes later. We hung out in my tv room for awhile and joked around. I showed her some funny pictures on my computer. She kept talking about her boyfriend, Tony, who is old enough to be her father, and how they have been shooting up together. She talked about Tony's friend, Pete, whom she taught to cook his pain pills down into liquid so he could shoot them up. Now, he's a fiend for it, of course. She told me she's been shooting up in her foot. She told me that she thought she'd blown a vein because she had this really big, nasty sore on the top of her foot. I told her to show me because I was worried that it might be infected. She took her shoe off and there were all these little blood spots on her sock. They weren't brown, like the blood had been there awhile and dried. They were bright red. She took her sock off and pulled back the bandage to reveal a deep gash in her foot right where one of her veins should be. It was so deep. She told me that the day before, she had pulled the scab off of it and that there was a huge blood clot underneath it. I got scared and shook my finger at her and told her that she shouldn't have pulled that scab off because that's what skin does when it is healing. As it is now, she has a big open wound that occasionally spurts blood. She said she was scared that she had given herself tetnus or something. She was afraid that it would get infected and that she would have to go to the ER, then, her parents would find out that she'd been mainlining and she would never see her son again. (Her parents have custody of her son.) I thought to myself,"Why would you do that knowing that if you got caught, you would never see your son again?" I understand that she's addicted, but damn. She said the reason for the Xanax (which she has a running prescription for) and the beer was that it kept her from fiending for shooting. She began to cry and told me that the reason she hadn't talked to me or returned my calls was that she was too embarrassed for me to see her like that. I felt like my heart was breaking. I reached out and took her in my arms and held her there and rocked her while she sobbed. Her body was just racked with them. She was shaking and hyperventilating. She calmed down after about 20 minutes, then said she had to go and talk to her boyfriend about keeping drugs in his house. She said if they weren't there, she wouldn't be tempted to do them. I thought,"Well, if you weren't going out with him, you wouldn't even have this problem." But she probably would have found someone else to do it with. When she sets her mind to shoot up, she usually accomplishes it. I love her so much. She's like a sister to me. I've known her since she was 12. I don't know what to do. I don't think there is anything to do. She's been in and out of rehab since she was 15. She always relapses sooner or later. I don't want her to die. I don't know if I could handle it.