2 year old, vomiting and diarrhea for 4 days. Little urine output. Not eating. Drinking some. Seems in bouts of pain. Been to emerge once said to hydrate. Vomit had brown streaks. He feels cold.

Go to ER. This sounds like moderate to severe dehydration and needs IV fluid administration soon. Please take this child to an ER for immediate evaluation before he goes into hypovolemic shock . If you have problems getting to an ER immediately, call an ambulance.
Child is ill. If he has been hydrated once already in the ER and he is still like this, he needs to be going back to the ER immediately. If there is an ER in your area that is a Children's hospital, that would be the preferable place to go, where they are used to evaluating sick children. If not, take him back to the nearest ER ASAP. He's already cool to touch and not much urine output - he is very ill! Go NOW!