Even though your dose of vicodin is relatively low, your long period of use has likely resulted in some withdrawal. There are also different aspects to withdrawal, including physical withdrawal which would mainly consist of diarrhea, body aches, insomnia, and intense fatigue; psychological withdrawal which would be primarily agitation and depression; and finally something called 'PAWS' or 'post acute withdrawal syndrome'.
You may have an element of 'addiction' that is extending, and will extend, for longer than than will physical withdrawal. This is a very complicated thing to understand and discuss, but a person becomes 'attached' to taking the substance for reasons far beyond a desire for pain relief. One way to understand addiction is to compare it to a bad romance with the substance-- stopping vicodin has many of the same effects as would happen if you just went through a break-up with an emotionally abusive partner-- even though it is good to be 'free', there is a strange pull to get back together... and you are left feeling emotionally exhausted.
The treatment for that type of thing is, in my opinion, best found in doing step-work. Do you need a 12-step group? Probably not... but would involvement in a good 12-step group make you happier, give you some energy, and helpf you feel less alone? Almost certainly... provided you went with an open mind, looking for things to like rather than looking for things that annoy you.
For now, a good sleep pattern, some gentle exercise, and a good diet will probably get you feeling better in another week or so.
JJ
I have been through numerous vicodin withdrawal episodes.....you are definately experiencing those symptoms. It takes time to heal. Doc has good suggestions, add to that take vitamins, avoid coffee or other stimulants, avoid fatty foods and junk food. Drink lots of water and take hot soaking baths. Don't take any meds you don't absolutley need. Many of the drugs prescribed today are only adding to the problem of a lack of whole health.