Blood and Mucus in Puppy's Stool After Parvo Recovery?

I have an almost 3 month American blue bully Pit mix that just beat parvo. I thought everything was fine since I deep cleaned my apartment with bleach. But now he has started having a small amount of blood and mucus in his stool that's more of a pink color and I'm not sure what it is and neither does his vet. They told me that he does not have parvo anymore for sure. I'm just super worried about him and want him back to being healthy again. Any ideas on what this may be? Or has anyone ran into this problem?