According to your symptoms it appears as though you have had withdrawal bleeding subsequent to the use of the emergency pill, which contains high hormone dose. Usually, this withdrawal bleeding is mild, but, since you are experiencing heavy bleeding you may need further treatment to control it, in the form of styptics or further hormones. A physical exam by a specialist, blood counts and rest are needed. Please do not use emergency pills frequently as they can cause severe hormonal
imbalance and infertility
in future. Hope this helps.