Big bad discovery

I was just going through a booklet that my great-uncle Gene put together. He's been into genealogy for years, and this was something he made a few years ago. It turns out my great great great grandfather, Isaac Spivey, had a plantation with slaves. I hadn't known this before; I've always thought that my family were all immigrants from Ireland and Poland. Now I know different, and it makes me feel a little sick to my stomach. I even let out a few tears, even though I tried not to because should it hurt me so bad? But it's how I feel. In the story on him, it says he fought in the Civil War and came out unhurt, but that he lost $15,000 worth of slaves. I'm so embarrassed. I mean, I know things were different back then, but just the thought that I am descended from people who thought it was okay to hold human beings hostage and force them to work for nothing for their whole lives, and split up families, and deny them basic rights, like freedom to make their own life choices, and all of it, just makes me feel sad. What does it make me?