Pregnancy Gestation 5 weeks u/s results?

I just had an u/s at 4 wks 5days acording to my dates and the results show 2 small hypoechoic foci within the endrometrial cavity with neither embryo nor fetal cardiac activity, with the largest meausering approx 2.9mm which corresponds to a 5 wk gestational sac. I have looked everywhere for an explanation. Does this mean there is no baby/babies and these are a growth or a pregnancy that has failed to progress or is it simply to early for anything to be seen on u/s