Can Bleeding During Pregnancy Cause Miscarriage?

Hi, I am just entering my 7th week of pregnancy and this morning when I woke and went to the loo I had a small amount of bleeding (pink). About an hr later I went to the loo again and again I bled. Both times the blood was only on the toilet paper. I went to the docs and she did a pregnancy test which only gave a faint response. The sample also had blood in it and a small jelly like clot the size of a 5p. I have not really bled since and experienced no pain - am I miscarrying??