Abnormal bleeding??

I'm currently 6w4d prego and Tuesday I was at work with my fiance and on the way home, I started bleeding. At first it was kinda heavy with very little clotting. About 3 hours later a somewhat large clot came out but ever since then its been very light (like spotty) and brownish. Now it only happens when I wipe and its brown. Any ideas? This is also my second pregnancy but it never happened with my daughter.