Good luck Dan, trust me you are not alone in this. You are not the first person to go it on their own and wind up drinking again, I did it for 10 years, I finally went to a doctor, then on to detox where I learned that if I wanted to stay sober I needed to go to at least 90 AA meetings in 90 days and get a sponsor.
I thought 90 meeting in 90 days was impossible, my counselor in detox worked a deal with me, he told me just to spend as much time in meetings as I did drinking. I made 90 meetings in 90 days easy! LOL
What the detox folks did not tell me is not only would AA keep me sober, it would make me happier and a far better person then I have been in 30 years.
In a nut shell it is as you have found very difficult for an alcoholic to stay sober with out some sort of face to face support program.
I found out many times for many years that if the only thing I changed was that I no longer drank I was going to start drinking again.
If you change nothing, nothing changes.