KGirl - new life, new stuff

[KGirl]

Took most of the weekend to recover from Friday (after what was a pretty good Thursday!) I decided to go NC with my mom for awhile. Just because she is my mom doesn't mean she is there to support me (and I suppose a therapy topic/childhood issues that relate to relationships today - trying and wanting to get her support and validation and it coming sporadically or not at all). Had a rough Friday morning after going to the dentist, being delayed half an hour and therefore missing a work meeting, and then being told I had my first cavity to fill.
Texted my mom: "I have my first cavity! argh."
Mom: "maybe you had too much boy spit in your mouth"
me: "what? that was insensitive"
mom: "no it wasn't"
me: "You know I'm taking this stuff with XBF really hard, it's not something to joke about."
mom: switches topics to something completely different and I just ignore her.

This + the last time I saw her she told me "don't talk about it because then I'll get sad too" + her texting him to try to get his attention = not something i can handle right now. Do I need to tell her that I can't talk to her right now or just ignore her phone calls or messages unless there is a direct question? She gets offended very easily and will flip it back on people so I'm foreseeing a showdown of "I'm just trying to be HELPFUL but I don't know how so I'm doing the best I can, OK? At least I'm here unlike blah blah blah or that time you didn't come visit me in the hospital when I had surgery *insert other grievance I don't remember here*"