Congratulations!!!

I feel so sad that someone that has been close to you and supported you, would turn the cheek and say something like that. Maybe it was just the shock as she did not know that you were TTC, but that really is no excuse, she probably does feel that way as she said it.
I think that you should have a chat with her and explain your feelings and see how she responds. You obviously have had a great realtionship in the past, hopefull this wont change and she will become more accepting as time goes on.

Congratulations again and enjoy your pregnacy together