Dealing with a Narcissistic Parent: My Story

I highly suspect my mom has narcissistic personality disorder and it was hellish growing up, especially during and after teenage years. She's degraded me, dismissed me, manipulated me, screamed at me, etc. I've kept my distance as much as possible as an adult but last week everything came back and I've been reeling ever since. My parents anniversary is this weekend. She wanted to have the whole family free for the whole week to celebrate. We've all tried to accommodate that, but my cats vet appointment got rescheduled for Wednesday morning. As soon as she heard she took it as a personal attack that I have an appointment this week. I tried to explain it was just a fluke and we can still work around it anyway but she insisted it was because no one cares about her and I'm a passive aggressive bitch. She screamed at me, slammed shit around, cussed me out, all in front of my three year old son. My dad was appalled for the millionth time and apologized for her. Now I'm supposed to still do everything I can to be present and celebratory all week, excluding Wednesday morning, despite constant anxiety and flashbacks to childhood abuse from her. I just don't know how to get out of it without causing more problems, but I also don't know how I can face this again or bring my son around her anymore.