Sex 2 night ago!

So I had sex 2 nights ago and my partner didn’t pull out (first time since TTC) Last two days I’ve felt nauseous and had a mix of diarrhoea and constipation(green poop?!) plus brown discharge and some mild cramping.. according to my apps today I’m now high and change of fertility started the day we had sex.. with my peak tomorrow! Is this just a weird coincidence?!