My Last Period Is On Last Month 14th. .. Today

My last period is on last month 14th. .. today is 21st it is almost one month obe week...I don't want pregnancy now I want to postpone my pregnancy..so please suggest me what to do...I already consulted a doctor she checked me nd said am not pregnant. .but I periods has not came...she suggested meprate...2days is completed. .plz suggest me what to do..