I know plan b can mess up your cycle but I took it in January, had my period a week later but nonetheless, I had a regular period. I had unprotected sex in February around the 25? He pulled out but idk how well (didn't take Plan B that time). This month, I was 18 days late, then I thought I had gotten my period but only lasted two days... Possibly of being pregnant or is it just because of the Plan B I had taken back in January?