Late Period But Negative Test

Tazanique

My period is 4 days late, it was meant to come on the 31st, and I took a pregnancy test two days ago (a digital one) and it read not pregnant. Is there any way that it could have been a false negative? I don't have a history of irregular periods either, they're normally on time or maybe off by a day. And I also hadn't had sex right before, I know that can delay the menstrual cycle.