How To Treat Abdominal Pain,severe Flatulence And Headache Due To IBS?

Hello. I am a 25 year old male, For the past 3 month , I been having left side abdominal pain with Stomach Sounds and smelly gas and altered bowel habits / i also have headache and lower back pain.I ve colonoscopy my doctor tell me that i have ibs but its so Annoying pain my whole life has changed i don t know what to do with my life Sorry For My Bad English