What Causes Vaginal Bleeding With Huge Clots?

Hi I recently went to the ER Friday for bleeding I ve been having since Tuesday. Saturday the bleeding got a little heavy and I passed large clots. I went back to the ER and they refused to give me an ultrasound because I had one the day before. So they had me pee in a cup, have blood drawn and a pelvic exam. They didn t tell me much but except the fact that it was a threatened miscarriage or an ectopic pregnancy. Now the women s clinic called today and said that they still see the sac but the ultrasound they were looking at is from Friday. Do you think I still am pregnant or did I miscarry.