allergic to cheerios?

You might be lactose intolerant if you put milk on your cereal. 

Otherwise you are eating too fast and not chewing the cheerios properly. 

IDK. Do you eat it with milk?  

Have you tried oatmeal or plain Cheerios?  

more like the wheat they use to make them

Try Rice Krispies.  Its an easy cereal to digest.  So is Cream of Wheat. 

Could be gluten intolerance (to the grain in the Cheerios) or lactose intolerance. If you can drink milk or eat ice cream with no problem then the problem is probably with the grain used in Cheerios (wheat probably). If you are lactose intolerant, just avoid dairy and you will be fine. If it’s an issue with grains (wheat, rice etc) you should see a doctor since real gluten intolerance (celiac disease) can be more serious.

It seems more likely to be the milk, but the only way to figure it out is to test the cereal without milk and test milk without cereal and see what happens. 

its possible, ask your doctor to test you for allergies

Buy organic oats, no pesticides like Round Up in them