Your vet should have given you the lab results and discussed the course of treatment that would be used for the stage of CRF your kitty is at..if not, I'd call and get a copy of the lab tests and make sure you have a follow-up apt. to see how your kitty is doing.
There is a lot that can be done to manage your cat's crf, which can affect both quality of remaining years and how many years, your cat will have.
If you have not yet, please visit these two superb sites: Tanya's Site
and Feline Crf dot com
Please consider that Wellness contains garlic, and crf kitties in particular are ill equipped to deal with a substance that may cause anemia (Heinz Body Anemia) as many eventually develop non-regenerative anemia. A cat's sensitivity to garlic does vary cat by cat, with some not tolerating garlic even in the lowest dose or reacting fairly quickly to having foods/supplements containing this, others never react.
Here is an article by a vet on the toxicity of garlic:article on garlic
I, and a number of other tcs members have,or have had, kitties with crf, so know that we understand what it can be like to have a cat with this chronic condition.