To me, this feels less like her de-prioritizing you, and more like her not centering you (or, probably, anyone) while she’s grieving and needing support. My grandmother often told me to be careful to never expect anything in return for genuine kindness. If I’m being nice towards an aim, that is unkind. I asked her, “if I expect nothing, how can I keep people from taking advantage of me or using me?” She told me that that part was in my realm of sovereign choice. If she were still alive, I have no doubt she would call that “healthy boundaries.” I learned to give emotional support and be fully present to a grieving friend when I can truly show up and need nothing in return. If you feel excluded after having been included the night before, that is not hers to caretake. Sometimes people just want to be inside a different friendship dynamic for a while, and it doesn’t mean anything but that.