My baby is almost 3 months old (two days shy). A couple of days ago, they started refusing the formula, taking only about 50–90 ml, and that’s all. They may spit up what they’ve just eaten, but otherwise they’re cheerful, energetic, cooing, and smiling. Is this level of food refusal normal at this age? During the day they’ve also become more fussy and sleep less; they seem to sleep well only when held.