Anyone know why this woman might have given me a dirty look?

Today when I was in public, walking to the gym, a woman passed me (probably in her 40s) and she gave me an angry look. As she was passing me, she looked at my face, then at my leggings and then at my top and then back to my face again. She kept doing this until she had passed me. I was wearing normal gym clothes, I wasn't wearing anything weird. I have a very hourglass figure and my hips naturally sway when I walk so I don't know if that got to her (I'm not bragging by the way, just trying to give you all the facts). I just felt like she was judging me and I also have social anxiety. Any opinions?
Anyone know why this woman might have given me a dirty look?
Post Opinion