Great Job. Thank you.
So he does not have a fever.
Normal is up to 39.
The most likely cause would be the vaccine.
He does go to day care so he may be coming down with an illness as well.
I would treat him symptomatically for now.
He should be back to normal in 1-2 days.
To help settle his stomach
, you can give him one tablet of human pepcid, or zantac, every 8 hours. Those are human stomach acid reducers you should be able to find at the human drug store. If you can not find those, you can give him 2 tablets, or 2 tablespoons, of pepto bismol every 8 hours.
him a bland diet
of plain cooked chicken
, or ground beef, with rice. Since he has an upset stomach
, try starting with just a spoonful of the mixture. Keep him on the bland diet until he seems completely normal. Probably 1-3 days. Then, gradually mix in his regular food.
If he starts coughing, sneezing, can not keep food or water down for more than 12 hours, or he has multiple episodes of diarrhea then he should see a vet. To make sure he has not picked up a parasite, viral infection, or bacterial infection.
I would just let him rest. If he is good in the house, he should stay home from day care until he is better.
I hope this helps.
If you have additional quesitons, please reply again.