Can a girl be pregnant if she gets her period but it stops for a day or so then starts again?

It depends on when you had sex and other factors but yes, if you have sex close enough to your period you can still have menstruation (period) occur. Another reason for vaginal bleeding could be implant bleeding when the embryo actually implants in the uterus. Some women even have slight bleeding through out their pregnancy

simple answer. If you've had sex and didn't use protection or it failed (condom broke etc.) there is a chance you could be pregnant. Be safe and if needed go get a pregnancy test.