Hi Sis,
That was a terrible thing for her to say to you, and it was most likely said to influence you to change to her way of thinking. She obviously is trying to change you to what she wants and is not taking your feelings or needs into consideration. People are most probably not laughing at you, facts be told, they most likely don't even notice you. People today are so self involved or just busy that they don't take time to look around them.
Relax and just enjoy being Kim, you are a beautiful, charming and lovely lady who needs to look at the source of nasty comment and act accordingly.