What Is The Cause And Treatment For Celiac Disease?

I had a test done 9 years ago at a holistic clinic. I had the IgG and IgA anti-gliandin antibody test. The IgG was positive at 42 and the IgA was negative at 8. The nutritionist declared I have celiac disease but I am skeptical of this for multiple reasons. I was being treated for extreme fatigue and depression. What is the chance I have celiac and what should I do next?