Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
From the symptoms that you describe, I believe that Bud may be suffering from GERD or Gastrointestinal Reflux Disease. This is an excess of stomach acid that is causing poor Bud a great deal of pain....this is making him feel nauseous and uncomfortable.
The treatment for this is as follows:
Fast Bud for 12-24 hrs to allow the digestive tract to calm down and heal.
Give Bud Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy.
Give only small amounts of water during the fast or ice cubes
After the fast, feed rice and boiled chicken (2/1)
If he is feeling better, it would be best to change Bud's food to one for a sensitive stomach such as Royal Canin for dogs with a sensitive stomach....do thsi slowly.
If this treatment is not effective, have your vet check Bud to be sure we did not miss something.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, XXXXX XXXXX