This is probably going to sound really bad. My boyfriend and I of 3.5 years broke up for about 4 months. In that 4 months I started seeing someone else. I had sex with him once on 09/20/14 (unprotected) After that, I realized I wanted to get back with my ex. I was back with the ex within 2 weeks. Anyways, I had a normal period starting the day after my mistake 09/21/14. and then again I had a period in October but it was almost a brown color. It lasted the normal amount of time and other than being brown was normal. Well I'm now pregnant. What are the odds that this baby could be my 'mistakes' baby? I'm so scared. My boyfriend is so excited and has told all his family. This could end really badly for the both of us. The reason I'm questioning this is because I swear I can feel this baby move already and I'm only 9 weeks.