I think your child has Acute gut infection.Vomiting
,stomache and loose motion
all support this.
The following advise will be helpful for you.
1. Stop Azithral
and give him Ofloxacin
2. Give him antispasmodic like Syrup colicaid for stomache
3. Ondem can be given for vomiting.
4. probiotics like darolac should be added
6. Oral zinc
Following signs should require immediate doctor attention
1. decrease urine output
2. recurrent vomiting
3. Decrease activity
Wishing good health for your child