Hi Julie, and welcome back to Just Answer!My name is XXXXX XXXXX it will be my pleasure to assist you today.I'm so sorry Mookie is causing you this worry, but you did the right thing in bringing him to the vet immediately!If he's eating wet food and drinking water, he should feel the need to go, sometime. Male cats usually are capable of holding their urine longer than females. I would watch for anymore licking of his private parts and if he goes to the litterbox often, but nothing or just a few drops come out. That would be the key to letting you know he needs to be taken to the ER vet to be checked for a possible urinary blockage. Here is additional information:Urinary problemsIf the vet said his bladder was almost empty at the time he was examined and he was able to get some urine for a urinalysis, it doesn't sound like he was blocked at the time; however, that was quite few hours ago and he could have a urinary tract infection which is causing inflammation inside the urethral, pressure and discomfort, so he feels like he has to go, but he doesn't really have to. The Convenia should help if he has a urinary tract infection, but we have to give it time to work.At this time, I would continue to observe him for the symptoms mentioned above, and, in addition, if he begins straining again and cannot urinate, a visit to the ER vet center would be your next step.I hope all will be well with Mookie!