Hylight, I actually think that what you're referring to is the Post-Acute Withdrawal Syndrome or PAWS for short. Occasionally, myself and others use the term protracted to describe a withdrawal syndrome that seems to be going on for longer than normal, whatever normal is.
Basically, you start out with the acute phase of withdrawal, which is severe and lasts for a few days or more depending upon the substance you were using and how long said substance's duration of effect was. Once you are over the acute phase of withdrawal, you will regain some functionality and some of the more serious symptoms like nausea, vomiting, fever etc. will abate. However, it will take additional time for your body to actually regain homeostasis.
This last phase varies from person to person and is extremely subjective and will also depend upon variables like duration of dependence, how many times you've withdrawn, quantity used etc. This phase is often characterized by anxiety, depression, apathy and intense craving. Once you actually do regain homeostasis, these symptoms will improve. This is a difficult thing due to its long duration and relapse is certainly not uncommon, but you can handle it.