Did anyone know they conceived right after?

So I have a wedding to go to in December and told my husband that I’d like to chill with ttc April and May...of course this is the most we’ve BD during my fertile week. AND on Thursday we had amazing/fun sex and he tapped my stomach after and said “yep that was it”. He never jokes like that and honestly I didn’t want to tell him I felt something very different. Now I’m nervous lol. This would be the 1 month he actually tried to get me pregnant! Any mamas out there just KNOW when they got pregnant?