Hello, I Am Now 10 Days Late For My Period,

Hello, I am now 10 days late for my period, I took a pregnancy test and it came out negative. I took one before my period was due as I felt some symptoms, that was negative. I took one again when I was 6 days late and it also came out negative. Is there a chance that it is not picking up the hormones on the test ? It was clearblue that I used as well. Just wondering if it could be a false negative or if I may actually not be pregnant. My periods are very regular almost to the day. It is very rare that I am late or early even by a day or two.