we had sex on last Friday and today's its thrusday(9days) after sex..my gf on the next day of our sex complains about feeling vomiting but I denied her since then she complains everyday and today it has completed 9days.I bought a pregnancy text but yet to conduct..we had sex on her second day of menstrual we had it twice but no sperm inside her..how can we avoid pregnancy if she happens to be positive plz need help.