That's progress. Did you see what happened? Sensing maybe it not being the ideal timing, you essentially asked her for feedback on her state of being. That gave an opportunity to validate her and take into account what she was feeling. Being listened to is more likely when it goes both ways. That gave her an opportunity to speak for herself -- instead of assumptions being made about her reactions (very important, as, as you have experienced, the assumptions tend to interpret things as being negative and personally directed -- which sends your thoughts spiralling -- when in reality they're VERY often not(!) (It can save a LOT of grief to remember that!)

As for that being somewhat upsetting, yes, that's understandable, but one way to help temper that is to remember that your levels of "being up to" handling various conversation varies too. Right? It's true for others too, and we need to try to cut them some slack that way. When others afford you that space, you appreciate it, yeah? Everybody does. Timing. We can't always choose it, but sometimes we can. (Prime true life example of not considering this... Right before going in to see stand up comedy, BF goes into this whole heavy upsetting thing that totally could have waited(!) He also has a knack for doing such things when I've just flopped into bed, utterly exhausted. He can jump to negative conclusions about my attitude, when the truth is actually very simple: I need the sleep. not only the time, but the content will likely to prevent this sleep. And being incoherent is no help to good conversation, lol.)

(Underlining mine) Other way around. What you describe there describes BPD. Not BP. (it might have been a typo, but in case it wasn't, just wanted to avoid any confusion it might cause any newly learning readers.)

I'm so glad you are giving these things thought, that's where positive changes begin!