I keep feeling baby push up against me right above my belly button and it’ll be like a round ball poking out right there. Is that his butt or his head?

I had a 3D ultrasound 2 weeks ago and she said he was head down so I’ve been assuming it’s it’s butt but sometimes I’m just not sure. I don’t really feel any pressure down low like if his head was there. Could he have turned and is breech now or is it more likely that it’s just his little round butt?