Neuropathy can be caused by diabetes but that usually happens after years of uncontrolled and high sugars. My grandma had it. Her feet felt like they were on fire, needles pricking it, & numbing. My sugars bottom out as well, but I am not offically dx with CFRD. Have you ever checked your sugar around the time that your foot goes numb? If so, is it over 200? Does your sugar drop a few hours after your foot goes numb? If that is the case, then they might be connected to sugar problems. Keep and eye on it and contact your doctor if it continues.
Added note: When you surgar drops try to eat a meal like a sandwich, pack of Nabs or drink Orange Juice. Eat something with protein, peanut butter if you can and are not allergic. OJ is great too because it has natural sugars and works quickly. If you have reflux problems like myself then try OJ with Pineapple Juice added. If you eat candy every time your sugar drops then you are gonna be in a vicious cycle of ups and downs. Insulin kicks in, sugar bottoms out, you eat candy, sugar sky rockets, insulin kicks in again, sugar bottoms out....see the pattern? Use candy only when you need a "quick fix" until you can get to some real food. Eating something with protein will keep your sugar up at a stable level longer than what candy will.