First of all, welcome to Pet Talk, although I know how worried you must be.

If this is day one of diarrhea I would not panic. Sometimes my Persian gets the runs for a day or two then it clears up all by itself. You say you have not changed the food. Could Macy have gotten into something or perhaps chewed on a plant? Sometimes eating bugs can give kitties diarrhea.

Having a Persian, I know how messy the cleanup can be. I would confine her to a room with a her own litterbox for about 24 hours. At least that way the "mess" won't get all over the house. Also I've heard on Pet Talk that pure pumpkin or plain yogurt that you buy in the grocery store helps to bind.

Good luck and please keep us posted. BTW, Macy is one beautiful princess.