Hi, I am 17 years old and have had sex with my boyfriend about 5 times over the past month. This past month is the first time I've ever had sex, and we used condoms, and made sure they didn't break. My period was about 4 days late, and only lasted for 2 days. I took a pregnancy test and it came back negative, but I'm still concerned. I've been feeling sick at night and I'm wondering your advice.