Betas not quite doubled?

M

So our first beta was 221 on Wednesday. Second was 419 today.

The nurse says they aren’t happy with that. It should have been 442 or higher. They’re having me test again Monday.

She made a pregnancy confirmation ultrasound appointment, but definitely made it sound like I probably wouldn’t need it.

Does anyone have any thoughts? Now I have to wait the weekend. And I just don’t know what this means.