8 Days late for my period.

Jo

So I wasn’t actively ttc last month like I planned. We did have unprotected sex a couple of times... a few days before ovulation and also four days after my period ended. I’m usually VERY regular. I get my period every four weeks from the last day of my last period. My period ended last month on the 11th... so four weeks from the. Would put me due 8 days ago. I did a cheap 88 cent test on Thursday when I was three days late and it came out negative. I didn’t want to keep testing bc I know I will drive my self insane. This is the latest I’ve ever been aside from when I was pregnant with my son. Anyone have a similar experience? Should I test again.... is it possible to have a false positive when I tested last week? Thanks In advance ❤️