Question !!

So I’m just making sure, I feel like I already know this but just wanted opinions. So my my fiancé and my friend keep joking cuz I’m eating all the time and that I’m pregnant lol which Ik it don’t work that fast? But we did the deed and he cam 3 in me and it was 6 days before my period so could I ? We not really trying but we not not trying. Please don’t comment if I didn’t wanna have one I should have used a condom🙄 but just some answers pls?!