what should i do in this bad situation?

I need some advices for dealing with this situation. So I had a huge fight with my friend A today, and she said she needs a break from me, she needs space and all that. I feel really bad but I don’t know what I did. And before we start the fight, I was talking about why she misses our other friend B, who had moved school, so much. I am friends with B as well but A and B were so close before but then they had a huge fight so B decided to move. But they are fine now.
So my problem is, if A talks to B about what happened, B will hate me for it because she believes everything A said. And if I talk to B before A did, B will know all about it before A tells her anything and might tell A what I said. A might also get angry because I told what happened between the two of us to B and she might not want that. What should I do?
PLEASE HELP ME.