How Long Does Regestrone Take To Show Effect?

hi my last periods was on 9th feb but till now i couldnt get my periods.Doctor tested for pregnancy but it was negative on 13th march than she prescribed me regestrone tablets for two days. I finished the doseage . two days got over stopping it but still i m not getting periods. what shd i do next sir ? I m 30 yrs old. WITH REGARDS,