As a very wise Johns Hopkins Dr. once told me, opiate WD is like having fluid coming out of every orifice except your ears lol.
The initial 24 hours isucks, you can feel your BP start to spike, your eyes start to dilate and become light sensitive and get watery (i always hated that for some reason) you start to get that uncomfortable cold sweat feeling on your back and neck.
then the real fun begins....at around 24 hours and for the next 4-5 days you cant sleep, eat, stop wiggling/get comfortable. It is pure hell. I always get the serious jimmy legs and cant stop kicking and pounding the floor. I think i had a seizure once coming off 80$ a day IV dope cold turkey. I was thrashing so hard i thought i was going to break my neck.
In rehab it always used to make me pissed off when the nurses or drug counselors would say "oh its just like having a bad flu for 3-4 days" PFFFFFT......3-4 days? try 2 weeks of hell. The bulk of the WD is like a week then you have a week or so of PAWS. Insomnia, random sweating episodes, muscle aches...then the depression and hopelessness sets in.
But believe it or not, you eventually start to feel good again. One thing that has always helped me was getting a good long deep tissue massage. Happy ending doesnt hurt either lol.