Family Gathering and Anxiety

I'm supposed to go to a family gathering tomorrow and I'm really struggling describing how anxious I feel about the whole thing to my family. Rationally, I know that people don't really care if I come, and if I do, they probably won't pay much attention to me, but I'm so anxious it hurts. What hurts just as much is not being able to talk to the closest people in my life about this.

I don't know what to do.