natalie I had a very good friend who reacted exactly like that and I was completely gobsmacked. But I let it go and she came round. Basically as I understand it, peoples reaction is based on how it will affect them and their lives/relationship with you. With my friend I believe there was a certain amount of jealously too, although she is not normaly a jealous person, she is now 46, has no children and I genuinely believe this came to her as a complete shock.
Give her time and don't be too hard on her for now. I bet she comes round totally and if not, then perhaps its no great loss. You have enough feelings and emotions to be dealing with at the moment, why burden yourself with her attitude, be a little selfish yourself, you are the one who is pregnant.
Good luck
warpig.