The absence of foetal pole with presence of gestational sac indicates a pregnancy with nonviable or absent embryo what we call as blighted ovum. In such cases, the gestational sac has corrugated edges. Moreover, you have started having brownish bleeding which confirms the diagnosis. You will have to undergo termination of pregnancy after doing blood test for assessing coagulability of the blood to rule out disseminated intravascular coagulation (DIC) which is a known complication in missed abortion; i.e. nonviable embryo remaining in the uterus. Get the diagosis confirmed from your obstetrician and if it is blighted ovum, get the pregnancy terminated at the earliest if it doen not terminate spontaneousely. Most of the blighted ovum pregnancies get terminated spontaneousely.