Ovulation

Don’t judge me but I have a couple of questions so first my period is irregular I got mine a little late in age and it’s never been regular for longer than 3 months ... so I had sex for the first time Thursday and I took a plan b afterwards... don’t ask why didn’t I get on bc before I lost my virginity because I didn’t plan on sex happening it just happened... anyways I read if you already ovulated it won’t work ? I thought women only ovulated for 24 hours and if the egg isn’t fertilized then it just goes away or something? I mean that’s what I was thought in health class I always put my periods on eve.. my last period was the end of June going into the beginning of July .. Idk I’m a little nervous now ... can someone explain to me?

I just had sex Thursday and idk I think I’m feeling stuff in my stomach?? I also had a really sharp pain all over my like abdomen ... I also have a uti so that’s probably why ..

I had sex the 22nd of this month