Before you go off gluten, you need proper celiac testing. Celiac testing only works on a full gluten diet. (Four slices of bread a day worth of gluten.) If gluten turns out to be your problem, you won't want to re-poison yourself for two months to find out if you have celiac disease.
Tests you need:
deamidated gliadin (also called gliadin peptide) IgA and IgG
If the total IgA comes back deficient you need TTG IgG.
Your normal doctor can order this. It's called a celiac panel.
To answer your question for after the testing, shop the outside of the grocery store on your first couple trips. Veggies, fruits, potatoes and sweet potatoes, plain raw meat and seafood, eggs, natural dairy (cheese, butter, milk), and plain nuts are all naturally gluten-free and there is no confusing label reading necessary. You can venture to the processed food aisles to pick up some dried beans or plain canned beans and rice. For seasoning, single spices and herbs are fine, but many seasoning mixes contain gluten. Onions and garlic are good.
For your first dinner, make a roasted chicken, baked potatoes, and your favorite veggie with butter. Bake an extra potato so you can make home fries with eggs in the morning. Leftover chicken and a salad for lunch (olive oil and balsamic vinegar dressing) and you're off and running. gluten-free. It's that simple.
For more meal ideas check our breakfast and dinner threads.
Leave the rest of the processed food alone on your first couple trips, until you start learning to read labels. If you want to get into the label-reading here are food lists.