I was irregular not having my periods maybe every three months for about 3 days then I started taking Yaz birth control and I started when I was suppose to start but I was very very heavy (unexpected) and then it got lighter after about 7 days but then I just kept going and still was having light period until I started my regular period again and I am so heavy and I see clumps of blood that goes into toilet..What does this mean? I feel fine just never had such heavy periods and that lasted this long.