My little Charlie was really sick yesterday, meowing a lot and lacting like his bottom was really sore. I looked closer and found blood. I took him to the vet and they told me that his urethra was completely blocked. They had to give him a catherter. They said he would have died if I hadn't brought him in. I went and got him some urinary health food last night, but I really don't know what else to do to prevent this. He is only a year and a half old, but he is pretty overweight. The problem is, I also have another cat who is 4, but he is not at all overweight. They are the kind of cats that go back and eat their food several times a day, not all at once, so feeding them seperately is not a good option. Help!