... on my iPhone app my cycle is 28 days long and my period is from 5-7 days long but I had an accident and I took plan b one step in the morning which was on my period april 13 but my period didn't start that day today is the april 18 and I haven't got my period I have a son who is 13 months old & I'm not ready for another one yet should I wait another week im scares d and worried as what will happend I had a headache three days ago and I have cramps also I feel like my period started but when I check my self there's no blood at all ... Please kindly advice me I'm just really upset