Will Taking Only 3 Doses Of Regestrone Still Trigger My Period, Since I Can’t Continue Due To Severe Side Effects?

Hi, I have irregular periods due to stress. I took thyroid and PCOS tests, everything came normal. But my periods got delayed by 18 days. My doctor suggested taking the Regestrone tablet once a day for 5 days. I took 3 till now. It does give me a lot of side effects like severe cramps, and nausea. Will it give me periods in the coming week with these 3 dosages of tablets I can t take them any longer because I have to attend work.