I am not an alcoholic but have had some life experiences with it. My mother in law was an alcoholic. It's not easy to overcome but can be done. She was sober aside from one time falling off the wagon the entire time I knew her. She became very involved in her church and that seemed to be a huge help for her. At her funeral we found out more about that part of her life than we knew, she didn't talk about it much. My hubby was approached by a couple of women that asked if they could speak at the service. When they got up to talk they shared that they were alcoholics and that my mother in law saved them by starting a "Came to Believe" meeting and helped them find faith & sobriety. It was extremely touching.
Be strong, you can do it. There are always willing ears here, mine included. Feel free to pm me anytime.
As far as the horse side of things goes, like Val suggested I would urge you to find a trainer that you can work through the anxiety with. One that is experienced in helping riders rebuild confidence.
Life is like a camera. Focus on what's important, Capture the good times, Develop from the negatives and if things don't work out, Take another shot.