Ehhh mummy, this sounds like it could be a few things, sometimes 3 months tu babies go through growth spurts or they just become more efficient feeders so intake looks less, tapi if he's refusing at night and sleeping longer tu kena check properly with your paediatrician la, sebab reduced feeding + refusing milk boleh jadi tanda something's off (teething early, tongue tie yang baru obvious, or even reflux). A few of us in my mum group went through similar scares and ended up being normal developmental stuff, but better safe than sorry kan, especially kalau it's sudden like yours. How's his diaper output and weight gain? Those things boleh give clues juga.