No heartbeat @ week 8

i am in a similar position now.. lmp was 24th Sept, went for a scan at supposed 5 weeks but only gestational sac, then 6 days later started light spotting, so went down for another scan, and doc say still only the sac so need to wait another week to confirm if its growing.. went down a week later and still only seeing the sac but at this point doc is telling me to be prepared to miscarry already.. after 3 scans in a span of 13 days showing the same thing. now 1 week has passed but nothing happened yet so i scheduled another appointment in a weeks time to check.