Don't drink.
See a doctor.
Go on antabuse.
You don't have to ditch your friends, just lay ground rules and tell them that your body and mind can't handle alcohol. If they don't understand that, then what kind of friends are they?
Heck, be a designated driver. Write down all the reasons you wanted a "dry January." What did it feel like coming down on January 1st? Probably not so well, right? Reason #1. What does it do to your life when you're caught in the drinking cycle? Reason #2. Add a bunch of personal reasons.
You have support. Associate yourself with the following equation:
You + Alcohol = Death. Or You + Alcohol = Unbearable Hell.