What Causes Constipation And Abdominal Bloating While On Medication For Diverticulitis?

My mom is on day 25? after being diagnosed with diverticulitis. She is finished taking all the antibiotics and is finally eating some real food. She is also taking probiotics. This evening she said she suddenly bloated up as though she is several months pregnant. She thinks it may be constipation as she usually has 3 bowel movements a day and today she only had one in the a.m. Should she be concerned? She is not in pain, just terribly bloated. I was concerned about a perforated colon after all this.... Your thoughts?