[exjunky]

The only way you can feel achy after seven days is if you detoxed from a very long acting opiate like methadone. If you detoxed from pills or street drugs (oxy, heroin, etc.) it's almost impossible for it to last that long unless you're talking about a positively enormous habit.

There is a psychological component that can last for weeks or even months depending on how bad you were hooked. This is letting go of the opiate security blanket: from now on, if you don't feel so hot, then you rough it out like the rest of the human race.