Gastritis for 20 days. Should we do?

Child was having high fever,103+ on 8 july 2018. Consulted doctor & found sore throat. Ibugesic plus, alex plus was suggested for 3 days. Fever didn't come down at all after 2 days of medication so, antibiotic augmentin was suggested. In these 2 days, patient kept complaining of stomach ache one & off. The day we started antibiotic, fever came down significantly, 99.8. That night, child started having terrible stomach ache. So bad, that the child was not able to sleep the whole night. She kept waking up every half an hour, would burp heaving. Consulted doctor again & immediately stopped ibugesic and changed the antibiotic as well. Jr lanzol was given. Pain remained same for next day & night. Child was very weak in the 2 days but recovered in next 5 days. But since 25th july, child is again complaining of stomach ache. Her stomach is bloated. We are giving her jr lanzol from 3 days but not much improvement. Today she passed mucus also (no stool, only mucus). What should we do?