My 10-year-old neutered male was diagnosed in May with diabetes. He was started on 1.5 units of ProZinc, and was changed to 2.0 units about a month ago because his numbers weren't where the vet wanted them when he was checked again. Everything was going okay. I noticed Friday night that his breathing seemed different, and he was making a quiet grunting sound occasionally. Something between a grunt and a snort. Tonight, two days later, the noise is happening more often and more noticeably, and his breathing is much heavier and faster. Something is definitely not right, although he is still eating (he loves his food), walking, meowing at me, and purring when I pet him. He just seems more lethargic, and the labored breathing is scaring me. His vet diagnosed him in May with a heart murmur as well. She said it was a 4 out of 6, but also said it may get worse at the office than when he's at home. She mentioned tests, but I opted to wait because of the price of the testing, and because she said it could probably go a while longer without too much worry. I am going to call first thing in the morning to see if they can get my cat in tomorrow. If not, I will take him somewhere else. I am extremely worried and losing sleep tonight as I've never seen him breathe like this, though he has always been a light grunter/snorter in his sleep. Three months ago, we had to euthanize our oldest cat (13) when the vet discovered a large tumor and he was clearly suffering. I am so afraid tonight that I am going to hear some bad news tomorrow, or that something will happen to him during the night, even though he seems stable right now except for that heavy breathing. It's so hard when you don't know what's wrong and you can't make it better for them. Very worried tonight and just looking for any experience or advice with this type of breathing in diabetic cats.