Too late to be pregnant?


The last time I had sex was October 19th-20th and Sep 1st-3rd. according to my PTracker app I am 23 days late. I was supposed to start on the 6th but obviously that didn't happen. I've taken multiple tests and they all seem to be negative? (newest to oldest, top to bottom) wouldn't the lines be getting darker or at least visible if I was pregnant? Many ladies have been saying they see lines.