If you don't have access to emergency care or are reluctant to take him at this point we can try some things at home but he may need to see a veterinarian if he isn't coming along well over the next 24 hours.
To try and settle his stomach
now you can try either:
1) Pepcid-ac (famotidine
) at one 10mg tablet per 20 to 40 pounds of body weight
every 12 hours.
2) Prilosec (omeprazole) at one 10mg tablet per 20 to 40 pounds of body weight
every 24 hours.
These will reduce stomach acid and should help if this is related to simple nausea and gastrointestinal irritation from eating something nontoxic that he should not have.
I would not feed him any food for 12 hours even after the acid reducers are started.
This should help stop gut spasms and restore normal gut motility.
Starting a couple hours after the acid reducers offer small amounts of water, or clear broth like low salt chicken
or beef broth, or ice cubes frequently he needs fluids.
You can give him pedialyte to replace electrolytes too but Gatorade is much too high in sugar which can make his intestinal irritation worse.
If things are going well after his food fast and the acid reducers start a bland diet of 1/3 boiled, lean hamburger (or boiled, white, skinless chicken), all fats and juices drained off mixed with 2/3 boiled, plain white rice. Feed several small meals a day.
Once he feels better (no vomiting for 48 to 72 hours and eating well) start mixing in his regular dog food very slowly. Less bland more regular with each day. It should take a week or so to convert him back.
If Fluke is continuing to vomit and is feeling poorly though, especially if he continues to refuse to drink, it would be best that he see a veterinarian now as anything you give him orally will just come back up worsening his dehydration.
Best of luck with your fellow, please let me know should you have any further questions.