What Causes Excessive Bleeding And Discharge Of Coagulated Blood?

excessive bleeding and coagulated blood during first days of period.Discharge happening every 20 minutes at the momment and not stopping. Not had this before. Blood looks very think and lumpy,average discharge size approx 50mm long and 20mm wide. Very dark red in colour, normal blood is discharging light red colour. coagulated blood discharge looks like the food "Liver".