Still no period?

Hi Everyone!

My husband and i (31 yo) recently started trying to have our second child and tried this app. Conceiving my daughter was easy and i knew as soon as i was 2 days late I was pregnant as i have never been late in my life. Now i took test after test and they came back negative until it was a week late and i got a positive :)

Now this time I am late and i took the early tests and all negative. I am now 6 days late and more tests negative (like no glimmer of a line or anything). I’m starting to get nervous something is wrong. Is this normal to be this late and still get a negative test?