Suffering From Infective Colitis.

Hello sir,I am priyank.2 years ago due to bleeding,constent belching i was diagnosed with Grade 2 Acid reflux.after having treatment symptoms gos away.then after 1 year i found blood and mucus in stool,experiancing Tenesmus.My doc has performed Colonoscopy and i was diagnosed with Infective colitis.my doc gave me antibiotics and after that i was well but after some time again i was experianced blood and mucus in stool,Tenesmus,pain in lower abdomen,crampings,gas.my doc has again performed Colonoscopy(In June 2018) and i have again diagnosed with infective colitis.doc has gave me antibiotics.after completed antibiotic course i am still experiencing said symptoms.and my doctor has never suggested any effective diet to follow.Kindly help as i am suffering from this long time.and also suggest what to do and which diet to follow.Thank You