So, I had unprotected sex roughly a week before my last period, and although I did have a period, with the usual cramping at the beginning, it was shorter than usual and seemed lighter, but I thought nothing of it. (It usually lasts 7-8 days, but only lasted 5 on this occasion). Since then I've been experiencing headaches, and in the past few days my breasts have been very tender and swollen, and I was also drinking with a friend yesterday and I felt really put off and didn't feel like drinking as the taste made me feel sick, this is when I started thinking I could be pregnant but I'm not sure if I'm just being paranoid. But as I've not long turned 16, could this just be that my bodies still making changes? I've had periods since I was 11 and they've been mostly regular, minus one occasion I had a pregnancy scare but tests came back negative and after 6 weeks, I had a period for 3 weeks, then came off for 1 week and came back on for a further 1 week. Any ideas? Could I be pregnant or is this just my cycle changing?