it takes A LOT to leave me speechless and your post and your friend's behavior accomplished that.
this is a plain childishly vile selfish reaction and if i were you, i'd wait to cool down a bit (and vent away on the amazing lifesaving bnb), maybe talk to another trustworthy, close friend or your OH, and then simply call her and confront her.
why i suggest to wait is NOT because she deserves it, but because of YOU - you'll give yourself a chance to think of EVERYTHING you want to tell her, she won't be able to brush it off as a momentary, hormone-driven, irrational preggo girl thing, and you won't be left with "oh shit i should have said/i forgot to say this and that".
but that behavior is unacceptable and she should really come up with PROFOUND apologies and A GOOD explanation (and no excuses).