I had a period on July 18 th 2016 and haven't received one for the month of August at all. I took a text and it came back negative it is now sept 17 and still no period and I just took another test and that was negative to. I got all the sighs of me about to start and still nothing  I'm so confused as to why I'm not getting on if I'm not prego and my doc said back in June that I have to miss 3 months in a row to check for  thyroids or pcos or other things but I never miss a period