I'm sorry myturn, its a kick in the guts. It happened to me too, DH and I nearly passed out when we were told in front of all the family. I took it to mean I would definately m/c ( so did dh he admitted later) and that didn't happen obviously, but its so difficult.
I really hope everything turns out beautifully for you and your sister. Hang in there, its an awful time, and so unfair you haveto go through this stress.