When should i bring my two to four month old child to the doctors if i suspect that my child is sick?

Four signs: If your baby 1) is fretful or irritable for more than 24 hours, 2) has fever that is lasting more than 48 hours, 3) has temperature higher than 103.5 degrees rectally, or 4) screams and cannot be calmed down in 3 hours.

Other reasons: Other reasons to seek immediate care would be if your infant is having difficulty breathing, persistent vomiting, not responsive or color change around the mouth, decreased breast milk or formula intake to the point of reduced urine output/wet diapers, or if your child is dropped and could have a head or other injury.