I had my last menses on 24 July for four days the color of blood was brownish. I generally get my menses a day or two days before but I did not get it on 24 August on 25 August night I did heavy work so on 26 August morning I had some brownish discharge then in the afternoon I started to bleed heavily with severe cramps in my abdomen I did find clots but heavy red bleeding today is my third day still I am bleeding heavily may I know why such heavy bleeding is occurring.