Not eating or drinking, stomach is gurgling

We had a large family gathering at our house yesterday for Easter, and our 8-month-old basset hound, Jonesy, acted very out of character -- he was very skittish and nervous when large groups came around him, and he stayed mostly in the other room the entire day.

Then today we woke up and he vomited three times in a row. It was a white milky substance, and he's done it before in the mornings so that doesn't concern me too much, but the problem is that all day he has not wanted to eat any food, nor will he drink any water. I thought maybe he's still anxious from yesterday, but it's 6:30 pm and he is still acting strange...

He had a bowel movement this morning and I checked it out and it looked normal. He started scooting his butt in the grass after that so I thought maybe he was constipated, or one of the kids gave him some people food at the party yesterday. His stomach has also been making loud gurgling noises all day, and what's with the refusal to drink water?? I'm starting to get worried. Any advice??
thanks!
amber