Bleeding After a Positive Pregnancy Test?

Hi guys! New to this.. hoping someone can provide some insight. I was about 2 weeks late for my period (always regular), took a pregnancy test that came back positive 2 days ago. Last night I started bleeding & assumed I miscarried. The bleeding was fairly heavy though not my normal heavy clot-like period mess. I went to a doctor this AM who said I likely miscarried but that there was still a chance I was pregnant as bleeding can happen. She told me to monitor my bleeding but that it was just a waiting game. I've essentially stopped bleeding all together now so bled on/off for maybe 12 hours. Have any of you experienced this before? I'm not really sure what to do other than sit and wait. At what point to I take another pregnancy test or know one way or the other what happened?