blighted ovum?

Chelsea
Looking for any kind of success stories.. had an ultrasound today at 7w (0-3D not totally sure) and there was only a gestational sac.. but it was measuring exactly right.. my hgc levels have been going up perfectly this whole time.. has anyone had a baby just show up late or am I being totally crazy for trying to hold on to hope? This will be my 3rd miscarriage and really hoping I'm not going through this again