Odd woman

I got pregnant 11 weeks after my fiancés brother knocked a girl up. They are trying to make it work and hate each other but pretend to be happy. She blocked me on Facebook and it doesn't bother me but today I had to see her and she gave me a dirty look and wouldn't take her eyes off my bump. I love my bump and everyone says it's cute and I have a glow is she jealous or does she just hate me? Just want advice on how to deal with her