Hiii My Son Is Of 3 Years From Last Ten

hiii my son is of 3 years from last ten days he is having stomach pain fir which i took him to a doctor on 25 April. Dr gave him Cycoplasm and periset syrup after five days he he had 15-20 loose stools I took him to Dr again on 1st May Dr gave him Zinconia and ask to give cycoplasm but inspite of these medicines he has stomach pain last night he did vomiting and today again he had 4-5 loose tools in morning.Pls tell me what to do????