Can four I-pills in two weeks cause delayed periods?

Hello doctor,

My husband is away from the past one and half years due to his work. I visited him for 15 days. I had my normal periods there on the 31st of last month. Since I got a bit anxious about getting pregnant, I had four I-pills in these two weeks for protection. I then returned back on the 15th of this month. I had very scanty periods between the 24th to the 28th. And that is it. I had no periods after that until today. I have checked for pregnancy four times and it always showed negative. I do not have any pregnancy symptoms as well. I am leading a normal life. At times, I feel some cramps in the lower part of my stomach. I have already visited my doctor. She suggested I take Regestrone 5 mg, two tablets a day for five days. But, I still did not get my periods.

Kindly advice me for the same.