Thoughts...

So when I went in for my ultrasound They said I was 7 weeks 5 days which is 5 days later than my last period date. I kept track of ovulation (i thought I did) by checking the mucous . if it's clear and very stretchy you are supposed to be fertile and if it's thick you aren't. Anyway.. I didn't have sex that specific time frame and ended up pregnant anyway . (which I've been waiting for that moment !) could I have ovulated when my mucous was thick n gotten pregnant ? I'm confused