Should I be worried?

For about the last month I have had a very sick kitty. He was admitted into the doctors for 4 days with bladder stones, and then a week later was readmitted for more stones and a UTI. The first medicine they gave him, he couldn't keep down, (which was the reason he hjad to go back a week later), but they switched him to another prescription, which so far, he has been able to hold down. He's eating good, and frequently using the bathroom, but he is continuosly licking his manhood. Usually after he eats or goes to the bathroom, but he'll be just laying there, and he'll start licking. I'm wondering is he doing this because everything is healing and he is doing good( I have been known to blow things out of preportion some times), or is he trying to let me know that something is wrong? What should I do?

My first questions would be is he still got a little burning or irritations from the UTI, Is he drinking plenty of water to keep his system flushed out from the meds , and my last question would be can he get a yeast infection from the antibiotics for that would cause him to lick down there. My moms dog gets yeast infections so i am sure it would be possible for kittys to get them too especially since they are more prone to urinary infections. Im not a vet but that is my what my brain tells me

What Med was he on before? Coco was on Clavamox and kept barfing it. Last Week she was changed to Cepalexen and threw up the 2nd dose. She has not barfed it since. She still has a Bladder Infection though but is better. It takes time to get rid of them. She licks herself too.

He was originally on Amoxicillan, now he's on Cefa drops. He threw up the first 2 times he tookm the Cefa drops butnow he holds it down good. He's been on it for 2 weeks already. But he is going to the bathroom better.