Why am I getting diverticulitis during chemo?

Hello… I’m new here. I have IDC stage II, Grade 3, Oncotype score 35. DMX with reconstruction. I started the Red Devil chemo 2 weeks ago but trying to understand why I’m not on TC. Theo days after my DMX I ended up in the hospital with my first ever diverticulitis attack. I had my second attack last week and was in the ER again. I’m hoping there is someone else that can share similar experience because I’m scared to continue my chemo regime this Thursday because diverticulitis is so painful. I felt like I was in labor both times. 😢