i'd say its unlikely a)due to the time you had sex and b) you used a condom....you should be fine, maybe stress from the holidays has made it late? stress can DEFINITELY be a factor..i was 10 days late once and conviced I was pregnant..my periods were pretty irregular however, i know about when it would come and counted my 28 days just as an estimate, usually shortly after that i could expect it to come..USUALLY, but like i said it was irregular...well that month i had a 38 day cycle..and as irregular as my periods were it had never taken THAT long for it to come...i was under a VERY HIGH amount of stress that month and i blamed it on that...after that month i went on birth control haha...so if you want you could wait a few days or if its really bothering you then go ahead and get a pregnancy test just to ease your mind

You could be pregnant. You may have had implantation bleeding, which may have lead you to believe you were on your period the first time. But if it was a normal looking period, then I don't know. Depends on if you have had sex since your last period. Depends on stress factors. I would take a test just in case.