I Had Sex 15days Before My Periods But He Dint

I had sex 15days before my periods but he dint ejaculate in me and soon after I had my periods on the expected date.. But the second month of my periods I skipped my menses and had 5 vomitings on the 7th day of my missed period after whic I took pregnancy test at home whic was negative.. Do I still hav to worry of being pregnant?