Did i abandon her in her time of need?

this has always bothered me since it happened.about 4 years ago my best friend of the time developed some problems, she began slitting her wrists, had severe bulimia and was afraid to go outside. i supported her as much as i though i could have at the time but it eventually took its tole on me, she would invite my round then ask me to sit and read her diary about how she wanted to die and i would end up in tears, then she would make me eat loads of food and sit there making herself sick etc, and once she even took me into the toilets in school and started to slit her wrists infront of me, i used to beg her to stop doing these things and she wouldnt listen. i started bunking school to be with her so i could make her eat and check she didnt slit her wrists. it began to really drag me down and i felt she didnt want to help herself, i started to become depressed seeing her like this. After years of trying my best to be there for her eventually we began to drift apart, now we barely speak..