Should be 8 weeks. had u/s and g-sac was larger than embryo and there was no heartbeat. should i be worried?

Yolk sac.: Yolk sac is a confirmation of intrauterine pregnancy and should less than 6mm in diameter. it is seen usually 3weeks to 5.5weeks. If a yolk sac grows more than 6mm, it is likely to be a failed pregancy. By the 6th week, a fetal pole is expected with a heart beat. Any meansac diameter without a fetal pole suggest failed pregnancy too. It is prudent to repeat ultrasound in one week and review.