Missed period

Bailee
Okay lady's I'm very confused, okay I had a miscarriage on November 28th 2015 and I got my period on January 4th 2016 and my periods last 5 days max and no longer, well on January 31st I was supposed to start my period through the February 4th, we anyways I haven't gotten my period yet and today is the 4th and I still haven't got it. I took a test yesterday and it came back negative.. Any reason why? I'm so confused and when I seen that it was negative I was worried and frustrated because I didn't get a period and the test came back negative... We are gonna get another test today and I'm gonna take it but any reason why? I guess I don't know really how to word it. Thanks y'all