So I am 7 days late and so I decided to take a pregnancy test this morning but for some reason the pregnancy test was invalid and did not pick anything up. So I decided to wait to take another one after a few hours of rest. So I just took another one and this time the line is a very faint negative so I looked it up and it all said that I was pregnant and that it was just because my HCG levels were low. Is that correct? Or am I flat out not pregnant?