I was ten days late this month, never have I ever been late before except finding out I was indeed pg. I had no signs of AF or pregnancy. I haven't been on bc for months, and took four tests when late all which were negative. Went to the doctors took urine and blood negative. Here I am two days after doctors and AF came. I had a 41 day cycle this month from a 30 normal cycle. So I say if those tests are saying no, odds are there right.