In early pregnancy some amount of spotting can be seen because of the causes like,
- Gestational sac
while getting embedded in uterus wall can damage some blood vessels leading to spotting,
-Some women may have bleeding on expected day of periods even in pregnancy,
-Increased blood supply to local organs can cause spotting even on mild friction.
But as you are having continuous spotting even being on progesterone tablets
and heart beat not seen even after 7 weeks better to get repeat ultrasound
once to rule out the possibility of miscarriage