I've never had so many worries over a little pup before

I gave him a treat (he's been doing well, no tummy issues and bam, poo the consistency of pudding. He's had them before and no problem. Here we go again. Cooking turkey and rice for my sensitive pups breakfast, at 12:30 tonight..and adding pumpkin because I know he will get stopped up again from the rice if I dont. I can't figure out what's going on
He's being fed Royal Canin Yorkie puppy and he's not been drinking well last couple days, but he will eat ice cubes (I melt them down to very small size, so easily chewed) any ideas ???