Hi, I'm 5 Week 5days Due On My Periods, I

Hi, I'm 5 week 5days due on my periods, I had a ultrasound scan today which tells the endometrium empty and nothing could be seen. What does it mean ? Than why haven't I still got ma periods ?it's been 2 yrs of ma marriage and we have been expecting. I was never tis late and I always had a regular period. I'm totally confused..