Your LMP was on Feb 10th. You had unprotected sex on March 1st. That is on the 19th day of your LMP. You can't be sure that it is on the safe period, because you have not mentioned about your menstrual cycle regular/irregular/days/duration.
You have taken 4 tabs of regular contraceptive
pill on march 4th. May be a little late.
Have you not done any pregnancy
test so far and don't you have any symptoms of pregnancy.
Do a Lab pregnancy test immediately, if pregnant do according to your wish. If not pregnant do USG abdomen and Complte thyroid
and ovarian hormone analysis and take treatment instead of worrying.