Adv. Effect of antibiotics. Recurred.

I had been taking lots of antibiotics and painkillers bec of rct treatment. Due to which i started getting abdomen pain. When i got it checked, the doctor said it was colitis. I was prescribed rifakem 400, later the pain spread to the back,  i was prescribed rifakem and cataspa. Within 2-3 days, i could see mucus in my stools, so i was asked to take unobiotic sachets. I felt better. when i started my normal diet, the pain recurred. Bt this time, my upper abdomen along with the lower had pain and tenderness, so i got an endoscopy done with biopsy, wich said I had chronic active non atrophic gastritis. Bt i still had pain in the lower and mid abdomen. I was prescribed rifnim 400, menoctyl and an antacid tablet and also unobiotic sachets. After 10 days, i felt better, but my mid abdomen still had pain. The doctor said i was fine and can start my normal diet. Its been 7 days now. Since yesterday night, i got diarrhea with lot of mucus in stool, my rectum is paining and has burning.