Hi, I had a question that I hope you answer. 4 days ago, I had vaginal sex for the first time ever, right after the sex, like about some minutes after the sex, I got period (it was day 28 of my cycle 

and We had used a condom). I started taking contraceptive pill on that night, but the next day, I forgot to. So I took 2 pills the next morning, and then I started feeling headache and nausea. Is it possible that the headaches and nausea are because that I'm pregnant? Or they are just side effects of the contraceptive pills? In general, is it possible to get pregnant on your first sex while your sex is in the last day of your cycle and you've used a condom?