I am wondering why you feel guilty, Scarlett? You sound like a very nice person to be so concerned, but she is not your responsibility. I say, take care of YOURSELF. I do wonder if part of why you feel responsible may be depressive or anxious thoughts creeping through. She's practically given you an out by saying she's surprised you've stuck around this long due to her negativity. Unfortunately, you can't save everyone. And you need to deal with your own health. Perhaps someday, you can become a therapist or a type of peer or counselor who lifts others up, in honor of her or just your caring spirit. But I hope you know that setting boundaries and even ending a friendship that is toxic is not something to feel guilty for. Though I can actually relate to this (I've felt guilty for setting my own boundaries and ending toxic friendships before). Maybe it's natural for nice people and people pleasers, to feel guilty over this stuff. Doesn't mean the guilt is accurate. I wonder if she feels guilty for telling you there's no God. It does sound to me like she has changed since you knew her in college, and that's quite a normal thing in the evolution of friendships at times too. Sometimes, people change and it's not for the better.

I hope you know, that you can do whatever you like here, and I hope you don't feel pushed to do one thing or another. Just giving my opinion. You and your health matter. Hang in there, ok?