Sex & broken condom

Not really paying attention hubby and I finished the deed while using a condom, no other form of BC, and the codon broke (right when he was finishing) according to the app I am 3 days late now. We have 2 girls already, 4.5 yr old and a 16m old. I’m just at a loss for words. How? Is this possible to be pregnant? Am I over thinking this? I have small hopes that if I post this then I will get my period. Im okay with a third kid .. but I’d kinda been set in my mind with 2. 🙈🤷🏻‍♀️

Edit: after it broke I checked the app and I was on the highest day of fertility