I have not eaten oatmeal in a long time and today I decided to try it and now my stomach feels bloated and gassy can I be allergic? Thank you

Was it the Milk? Oatmeal is normally pretty easy to digest. An allergy to oatmeal is probably not the cause of this. Sometimes milk can cause these symptoms. Lactose intolerance can cause gas and bloating. Can you drink milk without any problem? Ask what kind of milk is used to make the oatmeal, perhaps that will lead to you finding the source. Good luck!