Good Morning Buzz and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry that Jack is not feeling well...
Most likely, Buzz, Jack has ingested something that did not agree with his digestive tract and has caused a digestive disturbance. If this is minor, this treatment will resolve this:
Fast Jack for 12-24 hrs which he is doing himself to allow the digestive tract to calm down and heal.
Give him 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 as you have wisely done, Buzz.
After the fast, feed rice and boiled chicken (2/1)
If the vomiting has resolved, then wean Jack back onto regular food. If the vomiting persists especially during the fast, take your sweet Jack to your vet for an exam and lab work to determine the cause for this. This is extremely important since this can cause dehydration or other more serious concerns such as an intestinal obstruction or infection.
Does that make sense to you, Buzz?
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, ***** *****