Anyone had a bfn day of missed period but then bfp?

Currently 2 days late, my period usually comes a couple of days before the app says it’s due anyway so it’s very unlike me to be late. I tested yesterday and today but bfn 😔 we’ve been told we won’t be able to conceive naturally but just can’t help but get my hopes up! Has anyone had a bfp a few days after af was due?