Wow, John Denver? PBS? You must be depressed. LOL Just kidding, I really do have some insight to share:
Occasionally, I do the same thing (take all of the bottle of painkillers as perscribed), only I don;t have any pain. I do it just because! (I haven't in a while because I'm on real meds now)
Anyway, the withdrawls can be depressive, and I have noticed that some generic bottles I've gotten are frighteningly potent, and some are hardly potent at all. Generics seem to be inconsitent, but the withdrawls seem to be as bad as the high was good (if that makes sense).
Regardless of generics or not, painkillers have sucky withdrawls that never seem to end, but they should be gone by the time you read this...
i feel that this is very normal, give yourself a week, eat lots of fruits and veggies, take vitamins and drink lots of water, eventually it will be out of your system.