Actually My Last Period Is On 26th Feb, But Still

actually my last period is on 26th feb, but still now i didnt gone through through the date. till friday i am having sitarama kalyanam, i gone through the doctor but the pregnancy result saying that its negative. I gone to throid, PCOD test. Everything is negative. But from last one 1 week i am having severe pain. Can i use this pills for 5 days to postpone my periods.