Conception date

Tamara • 30 years old with 2 daughters 14 and 8 and pregnant with our first boy!
This confuses me to say the least but maybe someone can explain... I got off my period May 9th and had peak ovulation May 17th but when they did an ultrasound at 7w4d (and everyone since) it's showing I got pregnant May 10th so could I have ovulated early and maybe the ovulation test was showing I was pregnant on the 17th? I know I'm due on Valentine's Day