I'm thinking chemical pregnancy. The line is not there today, or so faint that if I see something while twisting and turning it and squinting, it might just be my imagination. Unexpected to begin with, but it would have been great.
I think dh and I need to sit down and have a serious chat if we are going to go for a #5 or not. And take better precautions if not--I do not like the ups and downs of surprise pregnancies and losses :/