Hello and welcome, I Dr. B and would like to help you today.
Now if he did eat feces, this could certainly upset his stomach and cause these signs.
Now as long as he hasnt any belly discomfort, paling gums, and can at least keep water down, then we can try some supportive care to settle his stomach. To start, we can try him with an OTC antacid (ie Pepcid, Zantac). If you let me know how weight, we can work a dose for him. Of course if he has any known health issues or is on any other medication, you'd want to check with his vet first.
Once that is on board, we can plan to try a light diet. We can use small meals of rice with boiled chicken, white fish, cottage cheese or scrambled eggs. The aim is these are easy to digest and thus reduce gut upset.
Further to this we do need to keep an eye on his hydration. To do so, we want to make sure his gums are moist, and that he hasn't sunken eyes or skin tenting. Any signs of this confirm dehydration creeping in and would be a sign to have him seen ( especially that is often what makes them feel poorly).
Overall, eating bacteria filled feces can cause your lad's signs. Therefore, we can try the above just now to see if we can soothe his stomach. Of course if he cannot keep the above down, is dehydrated already, or doesn't settle in 24 hours, then we'd want to plan to follow up with his vet. That ways they can rule out other harmful concerns and start anti-nausea medication by injection +/- antibiotics to nip this in the bud and get him settled.
Please take care,
If you have any questions, don't hesitate to ask. Afterwards, please make sure to rate my help ( using the stars ior typing a rating) as this is the only way I am credited for helping you. Thank you. :)