three days after having unprotected sex I had spotting, then light bleeding. I had cramps and brown spotting the day before I had sex. My period was due a week after I had sex, but when I did bleed it wasn't a normal period (which is normally very heavy and lasts 6 days, not 3). Since I have felt very tired, emotional, sore breasts, dizzy, have increase need to urinate, some cervical mucus too, nauseous and not like myself. It has been 20 days since I had sex. Could I be pregnant? I was birth control but had been taking antibiotics (Calvepen) two weeks before I had sex, could it have affected my cycle and I was having ovulation the day before I had sex?? I am so confused. Thank you for your help.