Now that there has been some time, I wonder why you think this had anything at all to do with you. Clearly this person had something going on in her life because she was on edge with everyone. If it was something you caused, she would only act that way toward you.
I get told way too often that I feel like I'm the cause of other people's behavior when it has nothing to do with me, I just have bad timing to interact with them when they have their own thing going on.
Yes, I understand how callous I sound, how I don't understand how deep it goes. Wrong. I get how insidious the thoughts are, and how impossible it is to fight them.
The test is simple - what did you do to cause the rift?
Did you actively go after her? Guess what - read old posts on this forum - that's not even enough to push people away. Did you say something that offended her politics? Well that's about her. Everyone has the right to express their own opinions, and we all can agree to disagree.
Look at the test again - what did you do that was so bad to deserve her treatment?
I know you want to take the blame for everything. When it doesn't make sense, when you can't stop thinking about it, that's because you're not to blame. Which means the universe is broken because that's impossible, I know.
I can't just snap my fingers and think "they've got something going on in their life that I don't know about" and let it go. I ruminate and find a way to blame myself and when I can't find a way to blame myself decide it's proof that I'm such an awful person I drive people away without even doing anything. My superpower, I should join the X-Men.
But when my experience is 100%, and what I've been told is 100%, that I truly didn't do anything, and when I finally hear what was going on after the fact was, yeah, there was something happening that bad nothing to do with me, and when I do it to other people (and I do) 100% of the time it had nothing to do with them, I can use that to argue against the gut feeling that I somehow drove the other person away. It's not a perfect system, but it takes the edge off.
I also highly recommend the book The Four Agreements by Don Miguel Ruiz. He describes what I'm talking about in a much better and clearer way. Also it's another example to use to counteract the feeling of "I don't know what I did, but I must have done something, and it must have been awful, unforgivable."