My girlfriends period is now 1 week late. the last time we had sex i wore a condom and i never really cummed. and we had a lots of fight this month.

Other causes of late: Although pregnancy is the leading cause of late and/or missed periods, there certainly are many other reasons for a period being late. The stress of your fighting is enough to cause hormonal shifts and problems with her period. I do suggest she checks at least 1 pregnancy test to assure she is not pregnant - condoms are not 100% and it does not matter if you feel like you never ejaculated.