I had sex 1 week before my expect period, and again 2 days before my expected period. My period was late and this is very very abnormal for me. I had light brown spotting for maybe 3 days that was really on and off and I read that it could implantation bleeding. Then I seem to have gotten my period now, but it is about a week late and it is still not as heavy as normal. My breast have been tender and I haven't been feeling well. Is it possible I could be a week pregnant and still have gotten my period a bit?