I had unprotected sex on 5/30 and on 6/1 got my period . My period lasted 4 days . I have been feeling like throwing up.but I don't , having lower back pains , feeling tired and lazy , going to the bathroom more than often , and my breast have been feeling sore ? I took a pregnancy test TWO weeks after sex and it came back negative . I still have those same.symptoms even since I had sex . Could I be pregnant

Since you had sex, particularly unprotected sex, pregnancy is a possibility.