Hi Doctor My Last Period On Nov 10th I Took

Hi Doctor my last period on Nov 10th I took pregnancy test in Dec 17th it's positive.. I meet with doctor and she said every thing ok but we will wait to scan and my appointment is 30th Dec 2016. But suddenly yesterday mng I went to wash room I found I'm bleeding ( 21st Dec) still it's continue im passing some small clots and tissue no blood only I'm passing with urine. I'm very scared what I do now I'm going to miscarriage or what I can't understand pls help me