? Elder cat diagnosed month ago-been gaining weight/bloated stomach

I posted about my 16 yr old cat Blackie recently with gaining weight after starting insulin on April 26.
He's always been around 10 lbs and when I took him into the vet for a bladder infection (April 16), he was 9 lbs 2 oz.
Doctor noticed high glucose in urine, brought him back 10 days later to be tested for diabetes.
That day he started his shots.

I have noticed consistent weight gain ever since. A few days ago he was 10 lbs 14 oz.
A few days ago I noticed he's been having incontinence and then noticed his stomach seems a bit large and sort of firm.
He is acting as normal as can be, using the litter box and eating.

The doctor is out of town tomorrow so I have an appt for Blackie Friday morning.

Has anyone else experienced this?

 

I don’t think this is diabetes related. Gaining weight, yes, but not firm belly. Acre you sure he’s not constipated? It’s good he’s acting normal.

 

He's had bowel movements, but not very large.
He has an appt tomorrow morning.