Upset about my mom's behavior at my graduation

I had something with my mom happen recently. I just graduated with my masters degree and I usually appease everyone by only inviting select people to anything. I invited all my family because it’s a big event. Well my parents divorced when I was a kid, and there was some trauma. My mom didn’t like someone who was there. At the end when I walked out I asked where my mom was, she had walked out in the middle of my graduation. Am I the butt for being upset? Because ever since feelings of not being enough and wondering why my mom can’t coexist with others has been bothering me. And with it being so close to the holidays I’m upset.