Ovulation timing

My period was due on April 14 (so now 9 days late). I took plan b one time late March (28th, because I freaked out with the pandemic) and had unprotected sex on 4.11.

I took a test today, negative.

Is it possible I ovulated over a week late and am testing too early? Or is late period caused by taking plan b?

Anyone been through this? Helppp 🤪