Ovulation

I get knowing when you ovulate is super important. But I don’t get it so I just needed some advice please. I have pcos so I’m irregular. My last period was aug 14. I had sex the 23rd. I had just a little light pink spotting the 28th. I’m “in my fertile window” now but I feel like shit. I’m talking hot flashes, My stomach just feels off, not interested in sex. Idk Do you think that was ib? Or ovulation bleeding?