What Does Delayed Periods And Negative Pregnancy Result Suggest?

I had my last period on 21st march,but now this month I didn t got my period till now, so I have done home pregnancy test today means 29th april with my first urine in the morning..result is negative..,Am I not pregnant..,can I use cyclenorm E and P to get periods..?In how many days can i expect periods after completing medicine..?