hi, I am 22 years old and I have had unprotected sex on 27th of April 2014. My periods are usually regular which come in a cycle of 28-30 days. In the month of April I got my periods on the 9th and in this month I haven t got my periods yet. According to my cycle my ovulation time should be somewhere around 21st April during which I fell sick because of cold and fever. I took a home pregnancy test on the third day of my missed period in this month(May) which turned out negative. I consulted a gynecologist yesterday who suggested me to take Regesterone tablets for 3 days. Please tell me if it is alright to take these medicines and also if there is a chance of pregnancy, if not, what could be the cause of delayed periods because I am never late on my monthly cycle.