I NEED HELP

I’m 18 dpo (days past ovulation) I was suppose to start my period Friday the 3rd and I still haven’t. I have had mild cramping but nothing too serious, Sunday after sex I had some light pink colored bleeding/discharge, but after I cleaned it up there was nothing more. I’ve taken maybe 4 tests and they all keep coming back negative, I haven’t taken any in the morning yet though. All have been mid day. Below are the past two tests, any advice would be greatly appreciated!!