Hey MrsScarlet,
Vicodin is an addictive drug, whether its being used "legitimately" or not. Your body will build a tolerance/dependence on it and you Will have withdrawal symptoms, especially if you've been taking it for so long. I've had broken wrists and numerous surgeries where I prescribed pain meds for legitimate pain, but getting off was not fun. It should definitely be supervised by a physician who is familiar enough w/ it.
There are other groups on here as well that address "addiction" to drugs (vs. alcohol, etc.), and I'm sure more folks will post here for you. This is a great place to be
Good luck with your journey.