Hello. Thank you for asking your question on just answer. My name isXXXXX will try to help.
Do you know if he is passing urine normally or if he is able to pass urine?
Has he had any new food, new treats, or people food?
Is he passing diarrhea every time he goes into the litter box?
I am afraid he may have another urinary tract infection or urinary tract inflammation.
If he is going to the box more frequently and only a drop is coming out, I think he needs his urine checked. Monitor him very carefully. Make sure he does not go into the box and no urine comes out at all. If that happens, then it is an emergency and he needs to see the emergency vet right away. If he can not pass urine, it means his urinary tract is blocked with debris and mucous. If he continues to pass urine, it is not an emergency but he is probably uncomfortable. If possible, he should see the emergency vet today. Although it is not a true emergency unless he can not pass urine. I would definitely take him to his regular vet on Tuesday.
To help firm up his stools, you can give him 1/8-1/4 of a 2 mg immodium ad tablet every 12 hours.