I'm not sure then ...... as others have said, it's certainly not unheard of for people to have AF during pregnancy, although on the other hand it could also be a very, very early pregnancy that unfortunately didn't make it - this is quite a common scenario, not sure what the statistics are though.
If after a few days you still think you might be PG then I would suggest going to the doctors and asking them if they will do a blood test. Good luck, let us know how you get on.