6 month old dog won’t stop pooping!!

Hi everyone. I live in Texas and have my first puppy at 29. It wasn't planned. Found in the woods abandoned with his other 2 siblings. The other two have homes now. We kept him cause he was the most skittish and stuff. First few days all he did was shake and lay down. Started warming up when I brought him to bed with me at night. We are not sure of his breed and age. With think 6 months and he kinda looks like that dog shiloh from the book well shiloh. He is definitely not gonna be as small though. HUGE paws. Basically boxing gloves lol. Anyways we are having an issue. We've more or less house trained him but at times he gets bloated and becomes a poop machine. Just left and right pooping. I literally took him out at 10pm, he pooped in the house infront of my closet at like 11, and just now at about 12:10 he pooped again near my ac vent. I have no clue what's going on. Any help appreciated. Have a vet visit planned already btw for Friday for a possible ear infection issue he seems to have.