I felt the same way. We actually said no to a match -- the baby had already been born, but because of some concerns we had with her health and the circumstances surrounding the pregnancy, we didn't go forward with the adoption. That night I cried and cried and was freaking out because what if we would have brought that baby home! I would have been an instant mom! Two days later we got a call that our profile had been chosen by our DD's birthmom! Then I freaked out about meeting her... freaked out about going to the hospital... freaked out about everything!
Finally when DD came home with us, everything felt okay. So, like others have said, unless I'm crazy (which is possible
) all these feelings are perfectly normal.
Good luck, too!