I'm sorry your going through this right now.
It sounds like they were doing a lot of thinking over those 3 months and this wasn't an easy decision for them. It's also a hard thing to have to say to someone. So they probably avoided it for as long as they could. Maybe hoping their feelings would change.
Hopefully this isn't the final decision
.
Maybe you can write them (not asking for visits) just asking them what their concerns were, how your DD was acting differently and if it was because of anything you did or said(not saying it is).
I hope you all can work this out.