Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services now if your child:
Seek urgent, same-day medical care if your child cannot be comforted or cries continuously for around two hours despite attempts to meet basic needs.
The child should also be assessed promptly for severe or worsening pain, repeated vomiting, a swollen or very tender abdomen, a stiff neck, or unusual drowsiness.
A baby younger than 3 months with a temperature of 38°C or higher needs urgent medical assessment.
Do not rely only on how well the baby appears.
Get same-day advice if your child drinks very little or shows signs of dehydration, such as a dry mouth, no tears, much less urine, or fewer wet diapers.
New swelling or pain in the groin or scrotum also needs prompt assessment.
Arrange follow-up sooner if you are worried about growth, development, hearing, mood, or behavior.
Book a routine appointment if the irritability keeps returning, lasts several days without a clear reason, or regularly affects eating, sleep, school, or play.
Every sign above is quoted from the sofidex article on Fussy or irritable child. If you are not sure, err upward — it is always reasonable to be checked.