I am so sorry. I would feel crushed, ashamed, guilty, and so upset if this happened to me. She made a whopper of a mistake by offering something that she could not honor. Good for you for holding her accountable and sharing your feelings and not silencing the six year old feelings- that's what she's there to work with.

I hope you two will heal the rupture. She made a bad mistake in my estimation- but just a mistake, nothing intentional, nothing meant to hurt you, and I hope you will let her make amends in session.