My boyfriend and I started to engage in unprotected sex, I made us stop very soon after it started because i didnt feel comfortable to continue without a condom. He says he did not ejaculate, but I was worried about any precum. I was going to buy the plan B pill but decided against it. I got a light period 3 days after the incident but its been about 2 and a half weeks since then and I m having very bad headaches ans nausea through out the day, Ive thrown up a few times, and my breast are tender. Is the possibility of pregnancy high or can I just be going through a bug? I havent decided on taking a pregnancy test yet.