Hard emotions (or lack thereof) after setting a hard boundary

Hi everyone, I had something difficult happen over the course of this evening and am looking for some support or helpful/kind input.

For over 20 years, my narcissist mother has made fun of my laugh. Every time I laughed, she would mock me and make a face, sometimes commenting on how ridiculous I sounded or how bad it was. When I got old enough, about 10 years ago, I started telling her after every time she did it that it hurt my feelings. As you all could have guessed, she didn’t care or take me seriously and continued doing it anyway.

Today I went to my parents’ house to spend the holiday weekend with them. As I have been living on my own for a few months in my new home, things have been a tiny bit better, but twice today she mocked my laugh not only in front of my family, but in front of my boyfriend too (who is relatively new to attending family gatherings with me).

We left a few hours later and as we were driving home, I sent her a text stating the following: “The next time you make fun of my laugh, regardless of the occasion, I am leaving immediately. I have told you many, many times that it hurts my feelings.”

I get a call an hour and a half later from my dad saying that he found my mom crying in the bedroom about why I was so mean and awful to her. He then proceeded to say that my text was incredibly mean and uncalled for, and my ungratefulness and rudeness towards my mother needs to stop immediately. I told him very clearly that I was setting a boundary after many years of my attempts being brushed off, to which he said that I was being ridiculous and that everyone thought it was funny. He then proceeded to list out all of the supposed ways I have wronged my mom in the past year, to which I reminded him that I have heard her out every time, apologized, and adjusted my behavior appropriately if I believed it to be a fair concern. He ended the call by stating he would “speak with mom”, but that I needed to remember this moment in the future when they want to “set firm boundaries” with me.

It’s been a couple hours now, and I just feel empty. I can’t be bothered to cry. I feel this anger sitting deep and buried in my chest, and like tears could come if they wanted to badly enough, but I almost can’t be bothered. I almost feel weird that I’m not feeling more fiery or upset about this, and don’t know how to make sense of what I am feeling, or if I even did the right thing in finally putting my foot down. My boyfriend, who is my safe space, is here with me, but I find myself wanting to be alone, untouched, and just blocking out almost any stimulation. I’m not really sure what I am feeling, or where to go from here.

TLDR: I set a firm boundary with my narcissist mother over text after she made fun of my laugh (she has been doing it for 20 years). I then get a very angry call from dad telling me that I am rude and hateful towards my mother. I am now feeling empty and strange, and don’t know what to do with myself, or if I even did the right thing.