This article on Mothering.com perfectly described my experience.
I am so glad I told the people I did early on. Because I told, I got to have the joy and fun of people being excited with us, and I also received enormous support and sympathy when people found out about our loss. I never could have faked being okay if no one had known what happened.
So, I tell other women to tell everyone-share your joy. It doesn't hurt anything. Hiding in the dark when you are grieving one of the most painful experiences anyone can go through is worse than having to "un-tell." I also think it is sad to go through the first three months of a pregnancy assuming you will miscarry. It's hard not to, but even those of us who have suffered a loss should try to be happy and cautiously optimistic about a new pregnancy.