Unfortunately, yes. Absolutely. If you take chances, you'll most likely get sick it's just that simple.
Many people who are starting out on the gluten-free diet are stunned at how careful they must be to avoid gluten (and the related glutening symptoms). Since they've been eating gluten for their whole lives, they can't imagine that a tiny crumb can make them sick now.
The truth is, you get much more sensitive to gluten when you go gluten-free; when you accidentally ingest a even a little, your body is primed to make a big deal of it. How little? The amounts can range from a good-sized crumb to an invisible particle, depending on how sensitive you are. This article, How Much Gluten Can Make Me Sick?, tells more.
If you don't, you risk extending your symptoms and delaying your healing. Fortunately, it does get easier as you figure things out ... and as you start to feel really healthy and energetic again.