Suggest Treatment For Harmonal Imbalance

hi im 23yrs old im 5'3 110lbs..i take provera 10mg for 10days i started on may 18-27 its my 9th day today im confused because i dont have my period yet.i seek for the advice of my ob and she told me that i have hormonal imbalance i take urine pregnancy test last may16 and it was negative so she told me to take provera.she said that expect my period end of may..do i have to worry?thank you so much..