Hello, my son has been pooping very frequently every day, around 6-8 t…

Hello, my son has been pooping very frequently every day, around 6-8 times. It's not diarrhea, it's mushy yellow stool, and he starts eating and gets fussy. He doesn't cry, but plays well. I wrote to the doctor, she said to take Simethicone and Regidron. Before that we were on Nutrilon formula, they started giving him Bellamy, after taking this formula, this began. I think it might be due to the formula? I bought back Nutrilon, has anyone had something like this? I am very worried, the doctor says it could be dehydration, but how can it be dehydration if there is only loose stools? Or even if the stool is