I hope this is the right group for my issue? Let me know otherwise.

Basically my 14 week old puppy has got worms, we were given treatment for him and told it would ease up in around a week. He's on a plain diet recommended by his vet of rice and boiled chicken. Since finding out he has worms, starting the new food, and giving him the medication he hasn't been pooing :( or if he has it has been once overnight. He used to go 2-3 times a day. He eats 4 small meals a day for his tiny tummy, and he drinks plenty of water (his nickname is guzzler because he doesn't stop drinking.) He is peeing normally and his personality is still the same, we can't notice a swollen stomach or anything :(

I was wondering if this is a common side effect of the worms? Or the medication? Or the food change?

Thanks in advance x