feel better

Today I was at a class at work and as I was leaving, I asked the secretary about how to process some paperwork. She doesn't know me and I don't know her on a personal basis. We don't work in the same departments. I've interacted with her once before. At the end of our conversation she told me, "I hope you feel better. You look like you don't feel very good." It was genuine. She was being thoughtful. But I felt really good actually and didn't think I acted like I was feeling poorly. What on my face or in my complexion made it seem like I was feeling poorly? I graciously thanked her and laughed to myself as I walked away. I guess we always have to be mindful of what our faces are portraying unbeknownst to us.