First, Kindly let me know when was your LMP, if your expected period was on 3rd March, your LMP was on 3rd Feb i assume. Fine, if this was the case, your fertile period was from 13th to 22nd Feb. Since you have had sex on 1st March, it should not cause Pregnancy
. You can just wait for them to occur, which may have happened due to Hormonal
Imbalance, if not you should get yourself examined by a Gynecologist after 2 weeks of missing your Period.