What Causes Constant Headaches And Sleep Troubles After Quitting Alcohol?

I have been a very heavy drinker for years. I stopped drinking 10 days ago, with all the right help, AA ect. I have seen a nurse, but had been 5 days without a drink and felt quite healthy at the time. I didnt have a detox.

Now i have almost constant headaches (behind my right eye) and my sleep is terrible. why ? Please help me.