Ok. Why did he vomit here this morning? It could be due to him having eaten something that is just not sitting well - ate some table scraps, got into the garbage, found something in the yard, new food, etc. It could also be due to something being stuck - a foreign body such as a sock, rock, stick, piece of plastic, etc. It could be due to pancreatitis. It could be due to other metabolic issues such as kidney, liver or adrenal issues. Being able to tell what of these it is due to requires a physical exam, x-rays, and some blood work.

At this time, I'd pull up food and water from him for 8 hours. This literally means nothing - no treats, no food, no sips of water, nothing. Be sure to close toilet lids, pick up other pets water bowls, and monitor if goes outside so nothing can be ate or drank out there. The goal here is to let the stomach rest. If anything is ate or drank during this time, it has a very good chance of upsetting the stomach more. After we get past this time frame of having nothing, then we can start to allow access to water making sure not too much is drank at once. This is done by giving 1/8 cup to 1/4 cup of water every 20 minutes for 1 hour. If no vomiting occurs with this, then after one hour of having the water available, you can start to offer bland food. The bland foods that you can prepare at home pretty easily are boiled hamburger / skinless chicken breast and white rice mixtures. This is prepared by mixing 3/4 cup white rice and 1/4 cup of the boiled hamburger or skinless chicken. You can then give 1 cup of this combination per 20 pounds every 8 to 12 hours. I would over the next couple days then progressively get him back onto his regular food.

The huge hurdle for him to get over is the vomiting. If this continues, if he gets very weak, if he has obvious abdominal pain, or is not starting to eat and drink after 24 hours - he absolutely needs a veterinary exam. He at that point hasn't responded to at home care and needs a physical exam and testing to see what further therapy is needed.

The favoring of his right side - is that pain? Could he have a soft tissue injury? If this is getting worse, then that is something that also needs to be evaluated. I hope this helps!!