I need some advice!

Hey never posted on here before but just needed some advice😅 my little boy is 10 weeks old and I’m a first time mum, he normally has 4oz a feed every two hours and is an alright napper, today he’s only been having around 2oz and when I’m putting him down for a nap he wakes up every few minutes and cries till eventually I get him out for a cuddle, not sure what’s happening really but it’s weird for him he’s not usually a crier