Step one: get your addiction to alcohol treated, @Warren Wilson. There is no way you could even attempt to address the negative thinking patterns and PTSD while your brain is in an altered state. And I know what you're thinking: "there were times when I did sober up, and even then, I still couldn't cope with the depression and bitterness I feel toward what Watchtower did to me." Please bear in mind that alcoholism truly does change your brain. If you've done brief stints of detox and been able to blow clean on a breathalyzer, your brain wouldn't have actually been clear. That takes months, even a year, before at a cellular level you're completely clear brain-wise. There are neurological changes at different levels - particularly the amygdala - which really need to be retrained and reprogrammed (hope that doesn't sound like cult speak for "brainwashing"!).
There's so much that goes into this, and white knuckling it for 28 days is far from clean and sober. You need to commit to this and get some local support. AA might be the best place to start. Look up local meeting places and times and rock up. It doesn't even matter if you're drunk upon arrival. The folks there GET it, and they're not there to judge. If you can muster up the courage, you can even take the podium and speak your mind of why you're in this state. It can be emotional, but simultaneously liberating to bear your broken soul and know you're being heard.
Get yourself a sponsor while you're there - it's all free. You need all the understanding and care that you can get when embarking on this path, @Warren Wilson. Deep down, I believe you're still salvageable and can turn this thing around. But it has to start with a physically healthy mind. Only then will the emotional resolutions follow.