Do you think this was fair of her?

Sounds to me like she was just scared and is reacting poorly. Although, I can see how lying to your parents about spending the night with your boyfriend would break a lot of people's trust. I suggest talking to your friend's mom, apologizing to everyone involved (including your boyfriend's dad,) and working on earning their trust back. I'm sure she wants the best for you and was just worried about all the implications that come with you spending the night with your boyfriend.