Husband is confused

I ovulated between May 31st and June 1st we BD both days. I got my first vvfl Thursday June 14th and 3 BFP the very next day June 15th. According to this app it says I am 5w3d today. My husband doesn’t understand how I’m 5 weeks if it hasn’t even been 3 weeks yet. I understand they calculate it based off the first day of your last period but idk how to explain this to him and now it’s making me all confused lol (little back story: we have been apart since January while he works and I get our house packed to move, me and the kids just moved back in with him finally may 30th but I was in my fertile window when I got here. I did not cheat on my husband I love him so much the thought would never cross my mind plus with 3 little ones at home and packing to move I didn’t have the time to even think about that) to me it all makes sense, I think my actual due date might be a little later because it claims I conceived on May 25th but I wasn’t anywhere near him and I wasn’t ovulating at that time, as well I don’t have a “standard” 28 day cycle it’s usually around 30-33 days. I’m just worried at our first ultrasound they are gonna tell us the baby is measuring further along or something and he’s gonna think the worst of me. Sorry ladies just needed to vent about this I can’t get it off my mind