OK, first of all, if you get C, you are not "silent". Not all celiacs have D. A lot of them get C instead.
So the products you had said "may contain wheat", and not "made in a facility that processes wheat"? I ask because there is a big difference. If something says "...facility..." I don't worry so much. If it says "Made on EQUIPMENT that also processes wheat", I usually pass on it because I don't trust the employees to thoroughly clean that equipment. If it said, "May contain wheat", I would put it back on the shelf.
You just have to get into the habit of reading every label, every time. We ALL made mistakes in the beginning. I now keep a small magnifying glass in my purse for those labels in tiny print, and I read the labels, not only on anything new I may consider buying, but even on "old faithfuls" that I buy every week. Sometimes the ingredients change, and this prevents me from being caught.