Help me please

Bec

So I had an ultrasound on Monday when I was 8w+6d and the baby had a heartbeat of 186bpm, come Tuesday the day after I was getting sharp, stabbing like pains all around my belly. All day but not continuous, on and off and never lasted more than a second. That night I passed a small brown string of old blood. Now Wednesday and then today (Thursday) I have had no pregnancy symptoms at all but some boob pain. Is this OK?