thanks for posting your query.
You and your family is most likely suffering from acute viral gastroenteritis
with involvement of upper respiratory tract
infection and partial effect on liver
causing loss of appetite.
These viral infections has life span of 3-4 days during which symptoms are present and may persist even after effective treatment.
You should consult with internal medicine specialist and should go for thorough check up.
You and your family should take complete antibiotic course, antispasmodics and probiotics.
Appetite will recovers once the infection gets controlled.
Maintain your hydration.
Dr. Mayank Bhargava