Misti, the constant gas is definitely a symptom of a food problem and not environmental. All of the issues could be due to food. I hope your vet recommends and a hydrolyzed diet and a steroid.
It is important that you take a list of the ingredients in the foods you are feeding to the vet. They all seem to have corn, wheat, and rice and it is probably one of those ingredients causing the gas. The prescription hydrolyzed diets I am familiar with are rice, starch, or potato based and knowing the current ingredients you are feeding may make a difference in which food your vet prescribes.
