Hello dear, Its a good sign that your ultrasound shows cardiac activity. But i would like to know if gestational age (baby age)according to your ultrasound is corresponding to your gestational age as per your periods ie.12wks. If it is then its good. Regarding the bleeding you are worried about , it will stop but would take time. All you need to do is to avoid activities which might increase the bleeding like heavy work, exercise, constipation and sexual intercourse. Subchorionic collection resolves and pregnancy usually continues. You get a repeat ultrasound after 4weeks. Meanwhile if you have any further fresh episodes of heavy bleed or abdominal pain, do see your doctor. Take care and best wishes !