Newly Potty Trained with Diarrhea!

Help guys! My 22 month old just potty trained around 2-3 weeks ago. He’s been doing very well, but now he’s on antibiotic for an ear infection. His stools were getting loose before starting the antibiotic and now he has full on diarrhea! Anyone had to switch back to diapers temporarily after potty training and not had issues? Or any other suggestions on dealing with diarrhea when he’s just learned to control the solid ones? We started a probiotic before even starting the antibiotic.