I had sex with my boyfriend 3 days ago and today. He ejaculated outside but I am still worried about getting pregnant. So doctor, can you tell me if I ejaculated outside, do I need to take emergency contraception?

My period started on the 10th and ended on the 15th, but on the 19th, I had sex outside. So, doctor, can I get pregnant if I ejaculate outside 4 days after my period? My menstrual cycle is 28 days. Because I don't want to abuse drugs, I haven't taken birth control pills. In this case, should I take the initiative to take emergency contraception to ensure safety?