Hi,You should consult with your pediatrician
as early as possible ,child needs complete examination and investigations.
Start with ORS
and Syp Zinconia for loose motion
De worming agent can be given for worms.
I advise following investigations as you are saying child is sick since 15 days
1.Complete blood picture with platelet.
2 PS for MP
4 Urine routine microscopy
5 Stool routine microscopy for ova and cyst
Wishing for good health.