What Causes Continuos Small Bleeding Even After Taking Clomid?

i am 36 yrs old diagnosed with pcos.i am on clomid 50mg twice daily with metformin 1000mg once daily.i am having continuos small bleeding from nov 2010.today it is my 7th day of period still bleeding but less with small clots.but blleding has become less with clomid.i am worried please help