Advice/experience/hand-holding needed!

Our baby is 4.5 months (19 weeks), and from what I've read has a good foundation of sleep habits instilled: he puts himself to sleep drowsy but awake, he is an ace at putting himself back to sleep when he stirs/fusses, good self-soother, doesn't rely on a paci, motion, nursing, swaddle, etc to fall or stay asleep, and naps are FINALLY sorted out into 3 reliable naps per day. Generally he has a happy/calm temperament.

Before Thanksgiving he slept from bedtime-6am a few times and I was in heaven. However, since then he's reverted and gotten into a rut of not eating enough during the day (he gets super distracted and it becomes this huge struggle to get him to nurse or do a bottle) and then he makes up for it by waking twice (sometimes 3x) at night to eat. Night feedings he is obviously ravenous and will gulp down 6oz + 4-5oz, and then go straight back to sleep with no problem. Then we wake up the next day and he's not that hungry and is just staring at the windows and stuff. I think he's eating about 18 oz during the day/bedtime, and then another 10-11-ish oz in the middle of the night.

This afternoon we just had our 4-month appt with the pediatrician, and she *strongly* recommended we drop the night feedings using full-on extinction. She thought it would be a crappy few days with him hungry at night, but thought it would motivate him to eat properly during the day. Her opinion was that he was growing and gaining really well (90th%) and that he absolutely didn't "need" to eat at night. I'm pretty desperate to start STTN again myself, so I really want this to work, but scared I'm going to screw it up and deprive him when he's in need. Bahhhhh. Is there a right/wrong way to go about this? Is it a bad idea? If anyone has done it successfully, I would LOVE to get your tips. Thank you