Hey! I had unprotected sex on the 19th of August on the 28th I started light bleeding(implantation bleeding?) it went from light pink to dark over the course of five days this came with abdomen pain and lower back. Then I missed my period on the 8th of September. I have taken 4 pregnancy tests and two doctor ones they all came back negative. I am now 11 days late, headaches daily along with being nauseous on a whim. So could I still be pregnant? Fingers crossed!