I get it. Mothers day 2012 I had just gone through a failed ivf cycle and I dragged myself to MILs picnic. I was a wreck. Then one of the nephews who was 6 called me fat... He was calling everyone fat but not the point. I felt like everyone was feeling sorry for me anyway and I cried the whole 40 minute drive home.
Sometimes you have to protect yourself so maybe that's what she is doing.