You have to mark it down as a lesson learned. If it prevents you from repeating the same mistake, then it is a valuable lesson.
Maybe she was talking to her mom, maybe not. Either way, she was still talking sh't about you. She got caught, so she had to make you feel bad about it.......therefore she "claims" she was talking to her mom.
Take a deep breath, let go of last night, and put one foot in front of the other.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!