Period late by 9 days Two tests Negative

Can’t remember when I had unprotected sex because I didn’t think my period was coming up and the app said I was supposed to get it on Jan 18 but no period took 2 tests both were negative and I normally have periods around this time (20-30th day of the month) so idk if the app was just wrong and my period is on a Normal schedule or if I’m pregnant. Today I had a light flow but may be full on period I just can’t tell yet...

I have another pregnancy test but I know they don’t start definitely working til 2weeks after missed period please help