I have seen this way too may times. Louis is a finicky eater, so when he decides he doesnt want to eat his dry food he will starve himself for about a day or even two
I hate those days.
So what usually ends up happening is that once he is desperatley hungry he throws up some bright yellow foamy bile. Then and only then does he eat. I feed him on a schedule so I know when he eats and when he doesn't. Doing this allows one to know how their appetite is and what exactly they eat as well.
Let us know how it goes, you can always call your vet and ask, or simply monitor your baby's intake of food and water. yorkies are known to vomit, have diahrea and other smelly problems ( I read many yorkie books) Im telling you these little ones know how to remain the center of attention
good luck!!!!