You sound like a kind, caring person, but there is no way you are going to be able to keep enough distance with this woman for the friendship to be a healthy one. I don't know what is her diagnosis, but she is highly manipulative. You will try to show her you are caring and not abandoning her, but eventually you will have to cut her off. She sounds like a person whose neediness suffocates others. You are also dealing with getting yourself well.