so I'm confused even though this is my second baby 😂

I don't understand how I found out so early that I was pregnant.

January was a normal period right on time beginning of the month, February same but then got it again towards the end of the month into March. then of course I expected it to be the same get it again end of March into April, I did not get my period at the end of March so I was "late". April 1 came had sex and then soon after my period started. April 1-4 period then stopped had sex the 5th and so on. April 26 or 27 I took a test and it was positive took two more the next morning and they were positive. I just dont understand how I found out 3 weeks after my period.

has this happened to anyone before?

we didnt even know we were pregnant with our first son till I was almost 2 months in.