Is this relationship toxic?

My best friend, who has become my favorite person, and I now always seem to be at each other’s throats. It’s incredibly painful because I do love her and care about her deeply, but I feel like I’m always the one to take the blame when things go wrong and when I try to make changes, I get pushed back into my box of where I’ve been. Background: My best friend and I formed a co-dependent relationship last year. She was struggling with her alcoholism and depression and me with BPD. When things closed down last year, it became worse for both of us. But, we were able to be there for each other and try to encourage the other to become a healthier person. We talked all the time, throughout the day and night and worked on projects together (we’re both music teachers). Over the course of the year, she’s come a long way in her alcoholism. She had a few shorter streaks of sobriety and now some longer ones. However, she is still very depressed and now her sons disorder (OCD with hoarding) has become more prominent. I’ve really been working on my BPD and trying to experience my emotions but control my reactions and work on seeing gray area. I often engaged in self harm when I had extreme emotions which took the form of cutting, prescription drug abuse, and withholding food and liquid. I’m proud to say that I haven’t self harmed in 3 months! The last few weeks though have been incredibly tough with our relationship. Every time she’s down it seems she takes it out on me. When she’s overwhelmed she shuts down about herself. This has been particularly hard with my abandonment fear. We usually call each other every night to catch up with our days. The last few calls have been painful. She starts off the call with “I have no patience” which does not set a great tone. Then when I talk about something that upset me, I feel like she starts tearing everything about the situation apart making me feel even worse about it and myself. And then it becomes well you’re emotional and splitting because you have BPD which then does cause me to split. She won’t address her own mental health and I’m sick of having to absorb it into my own health. I love her and care about her very much, but right now, I don’t like her. I loved the way things were when we were both working to be healthier and supporting each other. I am afraid to cut off this relationship and lose another friend as I have so few and many relationships end like this for me.