at 6 weeks my embryo measured 2.5 mm. now researching what size a 6 week embryo ought to measure, i've found some books say it should measure 8mm some say 4mm and i'm worrying mine is too small, but if it is, i'm not sure if thats because i'm small myself so i'm going to have a smaller baby?? how much should a 6 week embryo measure?? any help would be great xx