I Have Diveticulois . I Am 65 And Never Had

I have diveticulois . I am 65 and never had a flareup until 4 days ago when my dr, put me on an antibiotic Metronidazole because I cannot take levaquin or Cipro. I had been constipated and passed a small tool with mucus. I took a stool softner 1 tablet a few days ago and developed diaherria. I am now on a Brat diet..My antibiotic prescription is for 10 days..How long should I remain on the Brat diet and proceed with a low fiber diet..pain has disapated but still have gas and loose stool? any help you can provide is deeply appreciated.