Eh, this is tricky lah! A few of us went through this, sometimes babies boleh jadi fussy tiba-tiba, especially kalau dah lama pakai bottle. Try warming the milk or formula slightly, and maybe berapa hari don't offer botol, just cup or spoon, then introduce balik when dia lapar, sometimes reset macam tu boleh work. But sebab tiba-tiba jadi camni, best check dengan doctor first to make sure takde teeth coming in or ada other reason dia reject, okay?