Withdrawal bleeding = not pregnant?

So I’m confused. And yes, I’ve called a doctor already to ask this same question but I still don’t know if it’s true because I’ve heard/read mixed things.

Is the withdrawal bleeding you get on the fourth week of pills a sign that you’re not pregnant the same way that a period is?

I know that technically withdrawal bleeding isn’t a real period bc there is no egg in your uterus waiting to be fertilized or whatever but I just want to know if it’s a sign that you’re not pregnant?

The doctor I called said that if I have withdrawal bleeding then it means that I’m not pregnant