There’s nothing to feel guilty about. Based on the contents of your letter, you didn’t do anything wrong and thus there is no reason to feel guilt. The fact that she’s had a hard life has nothing to do with you.
You are not a therapist nor can you help her with any of the problems she may have. A therapist would be in the best position to help her. They have the specialized training to help people with problems and difficult lives. You do not have that training and thus have no power to help her. She needs professional help.
If you no longer wish to be her friend, then it would be wise to stop all contact with her. All contact means all contact. This means not accepting text messages, phone calls, visits, etc. It may be difficult, for a host of reasons, but likely necessary to protect yourself against an unstable person. If she continues to contact you, despite your having told her you want no contact, then you might need to alert the police. They can protect you against unstable and potentially dangerous people. Good luck and please take care.
Dr. Kristina Randle