How the heck do you know?!

So if you're taking the pill it stops ovulation and thats how pregnency is prevented. On your break pills you start your period and then you go back to taking normal pills but from what i've heard, you can still be pregnant even when you get your placebo pill period (yes thats what I call it lol). So my question is, how the heck do you know if you're pregnant?! Yes I know "duh you take a test..." But do you seriously have to take a test everytime he cums in you?  And when you do take a test you take it after your missed period which isn't missing because the pills make it come so when do you take the test??