Advice on color change in fecal matter

Hey- I;ma first time owner of a kitten - and this morning my kitten's fecal matter instead of being brown was now a creamish.white color? She is also acting a bit lethargic and hiding under the bed. My vet isnt 24/7 so I do have to wait till tomorrow morning to check withher. Also: the dry food that she was eating previously was slowly being phased out with another brand - could this be it? Any advice would be greatly appreciated. Thanks

I would get her to the vet to be safe, especially if she is acting lethargic. If you still have the bag of cat food (dry right?) check and see if the expiration date has already passed. Good luck and please let us know what the vet finds.