Ovulated 4 days after peak OPK??

I am currently 22 weeks pregnant with our 2nd baby - planned. I'm just confused because in the 8 week and 20 week ultrasound, both confirmed I got pregnant March 25th. But I had my PEAK opk on the 21st? So I'm confused. I thought you only ovulated 24-48 hours post peak opk?

I'm curious bc I'm interested in NFP after this baby because I had the liletta IUD after my first and it had my hormones allll over the place. From depression to anxiety - even paranoia. It was terrible and I would prefer to let my hormones try to regulate for the first year at least before I think about hormonal birth control options.

I also apologize if this is the wrong group to post it. I could not figure out where this question could go 😅