Thank you for your query.Hope this answers your query.
There is no reason to worry...but as a mother you may feel distressed...I empathize..
usually does not warrant weight loss
that too within 7 seven days....so don't worry.
He might have indigestion
from some time.
Give him a probiotic
/yogurt everyday and provide him with home made nutritious food at regular intervals.
Though his weight is on the lowe side of normal but he should recover soon.Remember your child will only gain 1-2kg/year from now on.
If you have any other queries kindly direct them to me.
Wishing your child a speedy recovery.
Have a nice day.