9 months old kid constipation

Hi, what can i do to help my kid. She is having constipation, so heartbroken to see her suffering, I'm wondering is it because of me gave her fruit cereal & fruit oatmeal for 3 meals yesterday & the day before yesterday. Usually she only took either 2 meal of porridge or 2 meal of cereal (not so often, only give like this when no cooking porridge for her) but yesterday i gave her 3 meal instead and all 3 are different flavors and different brand. But she has been eating these. Or also wonder, is it because i bring her out hence skip her poo time. That's y she nv poo. #pleasehelp #worried #advicepls