Confused about son’s eating!

Okay. My son is almost 8 weeks old and in the 98th percentile for both height and weight 😅. We’ve been working on bigger meals throughout the day so he’s fuller at night and will sleep longer, which worked amazing for about 3 nights. He was eating 6oz every 3 hours (pediatrician approved) until bedtime, one feed of maybe 2oz in the middle of the night when he woke up for a diaper change, then not again until morning. The last few days, he won’t drink a drop more than 4oz at a time, every 3-3.5 hours. And is waking up hungry at least 3x a night again. 😩 So he’s gone from eating about 32oz a day and being totally satisfied to mayyyybe 24oz and incredibly fussy. Is this normal?? I am no longer able to breastfeed and he’s on Similac Soy. Thank you!!!