Late period, negative pregnancy test

I've been pretty good with tracking my periods. Every month I start anywhere between the 1st and 8th day of the month. Which would put my ovulation close to the 20th? Somewhere around there. SO and I had unprotected sex on the 2nd figured why not I'm not ovulating and I havent started my period yet so we'll be fine. We've had sex a couple more times between then and now. I've cramped on and off like I was going to start my period but haven't actually started bleeding. I took a pregnancy test 2 days ago and it came back negative. Has anyone else ran into this issue (not really an issue per say) but I'm confused on what my body is doing 😅