Missed or late period? 🥴

My last period started July 28th & ended August 1st. I have taken pregnancy tests and they do come out negative. I am currently breastfeeding exclusively, BUT ever since my period came back pp this year they have been pretty regular, until now?

The most recent test was today & again, it was negative?

my daughter is 14 months, has anyone else gone thru this? 😕

Again, my cycle has been pretty normal