Opinions please

I usually have 36 day cycles and last month I had a 40 day cycle. I’m on day 39 right now and still no af or any symptoms. I tested yesterday but got a bfn. And I’m scared if I do end up with a 40 day cycle again that means I ovulated on October 7th. And I had unprotected sex on October 8th-10th not sure if I would end up pregnant then or not.