What Causes Normal Menstrual Cycle Only On Intake Of Provera?

goodday Dr.Andrew,i have polycystic in both ovaries,done checkup and taking provera and i was menstruating after a week, but when i never take provera i never menstruate again for almost 8 months now, had conceive and done pregnancy test at noon time, and negative, i feel light leg cramps,but no morning sickness or signs of pregnancy. is it okay if i take provera again?, what is the possible result?