i wouldn't worry about it. you are right that the fetal pole is the embryo but at 5 weeks it is so tiny they can't see it (and don't expect to). if you measured 5 weeks and that matches your dates then chances are everything is perfect. congrats!! :)
you were lucky they saw what they did at 5 weeks...usually they only see a sac. the yoke sac and heart are the biggest things oon the baby right now and the little heart blinks. they meant the baby was still too small for them to measure at this stage. CONGRATS on your little bean :)
love....kimmie
I agree with Stacie and Kimmie. The fact that your dr has already spotted a heartbeat and your only 5 weeks along is good. It's very hard to see anything at that point in the pregnancy.