You are physically addicted to alcohol.
I had the same problem, wanted to stop drinking but the shakes and other problems were very uncomfortable, so I would drink just enough to make them stop.
That was a horrible place to be, I would drink enough to maintain some alcohol in my system, but eventually I would crash. Unfortunately, once i finally sobered up and got a few weeks under my belt, I would forget how bad it was and drink again.
I strongly recommended that you seek some medical guidance to get sober.