What Causes Yellow Coloured Stools Along With Vomiting In An Infant?

My 15 month old son has been off the last couple days. He is teething but yesterday his poop was a yellowy milky color. He had about 6 dirty diapers. Not water like just really loose and creamy. He vomited late last night. Again this morning. No fever. He has had 2 dirty diapers today. They do seem to be getting runnier. Still the creamy yellow color. No bum rash but after he poops he cries and cried. I feel his stomach is hurting. Any help? He had a bit of chicken noodle soup and bread for lunch that he has kept down. Also he will just nurse. He is not interested in and water or pedialite