Hi, I'm A 24 Yr Old Male And Recently Was

Hi, I'm a 24 yr old male and recently was diagnosed (at an emergency hospital room) with diverticulitis . I have been told by my family doctor that this is very rare for a person my age and am wondering what I need to do to"cure " this. My doctor told me this can be fatal but didn't say why or what I should do to reverse this or what my prognosis could be? I'm scared not knowing what I'm doing wrong and what could have caused this. I'm 5'7", and weigh 194 lbs. overweight yes but not huge ?