This may be due to intestinal upset from a change in food, intestinal parasites such as worms, coccidia, or giardia, or he could have a bacterial infection starting too such as campylobacter, listeria, or salmonella.
This could also be due to a swallowed non food item, ingestion of something toxic including plants, mushrooms, chemicals etc. Another issue, particularly if the dog had very fatty treats before this started, may be pancreatic inflammation which you can read about herehttp://www.peteducation.com/article.cfm?cls=2&cat=1580&articleid=335 Or a condition called Canine Hemorrhagic Gastroenteritis (HGE) which you can read about here http://www.sniksnak.com/doghealth/hge.html So seeing the vet to find out what is going on should be a priority. An over the counter med you might try would be Pepcid or Tagamet or Zantac. Be sure to tell the vet when you see them if you use any of these. You can read about dose amounts (and cautions) scrolling down on the pages here http://www.petplace.com/drug-library/cimetidine-hcl-tagamet/page1.aspx http://www.petplace.com/drug-library/famotidine-pepcid/page1.aspx http://www.petplace.com/drug-library/ranitidine-hcl-zantac/page1.aspx If that helps then you can see if some bland food and plain pedialyte added to the water bowl will help. I would suggest trying boiled chicken meat or hamburger with the fat drained off, mixed with really well cooked rice in a ratio of 1/3 meat to 2/3 rice to see if that works. It's not a balanced diet but OK to use for a few meals while working on controlling digestive upset. But if he is vomiting a lot, then if you can see your vet with him today you should try to do so. Dogs that are vomiting can end up dehydrated pretty quickly. You can check for dehydration by pulling the skin gently up over his shoulders in a 'tent' and release it. If it goes right back down that is good but if some stays stuck up that's a dehydration indicator.
Normal temperature in dogs ranges from 100.5 to 102.5 Fahrenheit or 38 to 39.2 Celsius.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics