Last month around the time of the 26th my boyfriend and I had unprotected sex. However, I have yet to receive my period for this month, I should have gotten it around the 4th or the 5th. I am now almost a week late, I have taken a first response pregnancy test, with a clear one line (meaning not pregnant) thank god. However I have yet to get my period. What is stopping it from coming? I will be trying another pregnancy test on monday but I want some answers as to what may or may not be going on in my body.