Period 5 Days late

Wahkelia

My period is now 5 days late with no signs leading me to believe that it is on its way. All last week and part of this week, I’ve been dealing with headache and nausea. I took a early detection pregnancy test, the day before my period and it was negative. I waited 3 days after then, and took another test, and it was negative….I just took a 3rd test on yesterday, a digital test, and it was also negative. Usually when I’m about to start, I have all the symptoms, cramping, headache, sore breast and all, but so far I haven’t had none of these, only headache and nausea. My cycle has never been this late before. Any advice? Have anyone experienced this before? Am I worried for nothing? Could I be pregnant? Any helpful advice would be greatly appreciated!