root cutting

I cut a root that was bigger than I first thought and now I’m super worried. It’s a pine tree, very tall. The diameter is 21 inches and I cut 7 feet away from the tree. I only cut one root and it was 3 inches in diameter. Did I ruin the tree? Is there anything I can do? Thank you!

So this summer, I finally got around to putting in the stairs at the back of my property to lead up from the access road to my house. In doing so, I cut a large root from the ground. This seemed sensible at the time, but now it's keeping me up nights. (I'm completely ignorant when it comes to...