If you tried talking to her about how her laughter makes you uncomfortable and she still hasn't stopped, is it worth thinking about switching to a different therapist? I went through a similar thing with a former T who nervously giggled whenever I discussed traumatic incidents with her. It was just one example of how the woman put her own comfort and needs ahead of mine. If this sounds like your situation, I hope you can find a T who respects and listens to you like you deserve.