Suggest Remedy For Irregular Menstruation

I had my last period jan 3rd 2015 and I didn t see the next period till now I have done pregnancy test urine and. Blood all negative so I was asked to take gyneacossid which I didon the 18thof feb 2015 I haven t seen my menses yet although I have cramps in my abdomen feeling of the menses coming but it hasn t. How long will it take the drug to work