Please help :(

Hello mummies, any one face this problem before ? -Yesterday went to KKH for scan (the scan is via Vagina) but the doctor mentioned that can’t see any signs of baby heartbeat . I am 6weeks + currently . But compare with the last visit scan, the baby is growing . Doctor mentioned that I might have already miscarriage . Any possible chance that is because of baby is too small or too early to hear heartbeat yet ? Any mummies faced this problem and ended up with good news ?