Ibs question

Hi all (M 34yr old), i been suffering for about 9 months of irregular bowel movements. It all started when i had Chinese food one time, and after that i got really sick with diarrhea, nausea, throwing up. Ever since then my stools been so irregular, most of the time with diarrhea, once in a while normal, and sometimes with mucus that smells horrible. I went to a gastroenterologist , sent me for stool test and blood work. Everything came back normal except vitamin d deficiency and a little inflammation. He prescribed some medicine for the mean time, but now I'm making solid poop but notice they are smaller shape and flat. Wanted to know if anyone has dealt with flat stools?