Soo... addiction... what is it, exactly?

While addiction has a fixed definition, I think it's more or less subjective for each individual. To me, being addicted to something means that you like it (or the results it brings) so much that you don't want to give it up, and you'll compromise things just to obtain the thing or result you're interested in. If it's Vicodin, maybe it's taking more than you really need to or somehow convincing yourself that you need more when you know deep inside that you really don't.

Physical dependence, on the other hand, while similar, is easier to deal with. If you've been taking Vicodin for a while, especially with moderate or higher doses, you're going to go through withdrawal if you suddenly stop taking it. This is the nature of this type of medicine and how it works in our brains. The physical symptoms should be the same: increased perceived pain (shooting muscle / bone pains, enhanced perceived pain in current painful areas), agitation, trouble sleeping, flu-like symptoms, restless leg, etc. However, for somebody who is addicted, they will tend to be consumed by plots or schemes to get the drug -- not only to avoid withdrawal, but because they like what the pills offer (emotional or physical pain relief, euphoria, or all of the above).

Some people get addicted to pain pills because of the euphoric aspects, but some people get addicted to having lowered or no pain.

In my opinion, if you're using something too often (which may or may not coincide with your prescribed dosage) or spend any amount of time worrying about how you're going to get more -- you're probably addicted in some capacity. If you're thinking that only addiction or abuse will lead to withdrawal symptoms, that's incorrect. They can certainly make withdrawal worse, though. You can be physically dependent on something but not be psychologically addicted to it.

You could also call physical dependence 'addiction' as well, so that's more where subjectivity comes in. If you think you're taking them too often, then you should slow down. Ongoing regular use will lead to dependence, but as with most chronic cases with severe pain, you can't avoid physical dependence unless you're willing to quit using them.

I would halt taking them any more as of now!