Quitting cocaine was one of the hardest things I ever did. I probably sniffed up half of Peru in the late '80s. One day I looked in the mirror and said, "Enough!" I looked halfway dead and felt I was about to finish the job. I quit cold turkey that day. There really wasn't that much of a physical withdrawal, but psychologically it was really tough for about two weeks. I wanted to chew my lip off for the first few days, but it got better.
Keeping your mind otherwise occupied is one thing you can do. Watch movies, read books, pick up a guitar.
Whenever I felt like a pick-me-up, I'd hit the caffeine.
When the urge strikes, go for a walk or a run or take a long, hot shower.
If your body wants to sleep, sleep.
Drinking too much alcohol WILL lead to a relapse.
Stay away from the people who go along with the blow and situations that lead to getting high.
I'm sorry I can't do more for you, but this is how I got off of it 25 years ago.