At 8 weeks of pregnancy
, if there is no fetal pole/ no cardiac activity seen, the pregnancy is definitely not viable, and needs to be terminated.
In case you are not sure of dates, the gestational ( pregnancy ) sac has to be measured, and if it corresponds to the weeks, but still there is no cardiac activity, it is called a failed pregnancy.
You need not have signs of miscarriage
Please go for a repeat ultrasound
, and then act as per the advise of your gynecologist.
Please do not panic, as at 5th week, sometimes fetal pole is not seen, cardiac activity is not seen.
So since you are having no problems, the pregnancy should be fine by now.