Difference between subtraction bleed and interval?

Do you still lose a womb lining or could you be pregnant and own a withdrawal bleed while on the pill? When you are on the pill, you still enjoy a "period". It's not a real time, but the effect is the same. You don't in truth make a womb facing every month when you are on the pill, because it works by tricking your body into thinking you are already pregnant.
So if you are bleeding, that's normal. But it is still possible to receive pregnant, if you missed pills. In that case, you won't bleed at adjectives usually.