Hi,
Welcome to ehealthforum,
If pregnancy has been confirmed, consider getting serial HCG levels estimated. Doubling up of the hormone levels in 48-72 hours will show that pregnancy is going on smoothly. If levels are not adequate, then external hormonal supplements would be considered to be started to help you in preventing miscarriage/threatened abortion. Lower levels or progressively declining levels could indicate impending miscarriage. An early ultrasound scans can fail to detect fetal heartbeat. You can consider getting repeat ultrasound scan after 1 week for confirmation of gestational age and viability. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately.
Take care.