What Causes Heavy Vaginal Bleeding And Sore Breasts?

I am having some heavy bleeding about 10 days post ovulation and have had some early indicators like sore breasts of pregnancy. I know it is too early to test for HCG levels because my period is not due until the 21st of this month. Woke up thinking this was implantation bleeding, but it has continued throughout the day and is a dark red, as well as very heavy. Some cramping has accompanied it as well. I m wondering whether I should go into a health care facility or if there is anything they could even do. My biggest worry is a miscarriage or implantation failure.