HELP I AM SO CONFUSED!!!!!

Suzie
Ok so back in early May I had a chemical pregnancy and was of course very upset. I accepted it and me and my partner ruled to keep trying. End of May my period came like clockwork (I have short cycles so generally every 24-26 days) so going into June me and my partner were under stress and did not end up having sex until after my "fertile window". However 10 & 11 days before my period was due I have very very light pink bleeding only in the morning for two days (sounds like implantation but didn't get my hopes up) now I'm three days late for my period but my pregnancy tests are negative? This is with taking First response tests with FMU. I am so confused the only time my period has ever been late was with my two pregnancies (including my chemical). I was just wondering if any of you ladies had any insight or similar stories? Thank you so much in advance x