Me and my girlfriend have been doing 'stuff' for ages now and we recently had sex sometime between 10-27 December and she told me she hadn't had her period for four months, she usually isn't very consistent and has had problems before but four months is a lot longer than usual. At the start of January she had a some blood but she doesn't know wether that was due to a bladder infection. Do you think she's pregnant? I don't understand how she could be considering I always clean straight away and she was on the pill before and after te se(due to the problems) and I didn't cum inside her, can someone help?