What Causes Increased Beta HCG And Continuous Bleeding While On Clomid?

I am 29 femal , mother of 2 y son, have pcos since 10 years. i took clomid the past cycle and had chemical pregnancy the beta hcg was 52 then went to 41 and start my period 2 February and i still bleeding after 2 weeks, i made beta hcg yesterday and it was 120 !! why it raise up, and why i am still bleeding?