Three days late and pregnancy tests still negative 🤷🏻‍♀️

So the app predicted my period was due on Sunday (my last period finished on 27th of January) and I have taking two pregnancy’s test and both came up negative, have been experiencing lower back pain. Don’t know what to do next. Do i retest or wait to see if my period will arrive

***update***

My period arrived on Friday, so back to baby making baby number 3