Soooooo I’m late but....

Makaela • Lupus warrior 💜 WJL 8/22/22 💕

So we aren’t trying but not preventing. My last period was a day long and so far (according to this app) I’m 4 days late. Here’s the catch we didn’t have sex this month and last month is was after my ovulation date. I also tested last month and it was negative. What’s going on?