Baby diarrhea

Hi my baby’s 15mo he’s on toddler formula (Kendamil cow organic stage 3). For the park 3 days he’s been having diarrhea (4 times today), initially I thought was bc I mixed in goat formula same brand (he loved it more than cow), I stopped that but the diarrhea hasn’t stopped. Waiting for the pediatrician to call.. Any remedies? I’m doing Apple sauce, bananas, formula with baby cereal…:(. He’s also unirenal which adds on to the stress of him getting dehydrated. 🙏