At 7 or 8 weeks there can be just a sac though, right? You're only like 7 weeks or so, I thought. You at most could be 8 weeks?? That's not too far is it? I had trouble keeping up with the dates because we were both on birth control for a bit. There is time though, right? Just make your doctor give you another ultrasound in a week. You will probably see your baby then. Don't give up!