My understanding is that the antibody test can indeed come back negative if you are on a truly gluten-free diet for a period of several months. My understanding is also that there are different shades of gluten sensitivities, as well as different strictnesses of diet. If you are only mildly sensitive, then perhaps trace amounts of gluten (as in the wheat that is often used in spices to keep them free-flowing) might be low enough to allow your body to stop producing the antibodies. Uh, that's a backwards way of saying "it depends on how sensitive you are".
My antibody test came back negative during a period when I had adopted a gluten-free diet for several months. So, therefore I am not "officially" gluten sensitive. But I know that I am, and I always regret it when I have trace amounts of gluten.
It may be that you will have to decide for yourself if a gluten-free diet is helping you.