You have to figure out how to live in the present moment. The past really does not matter any more. It doesn't matter what you did before, it matters what you do today.
In the Women's subforum, there is a thread called one thing I did for myself today. As alcoholics, we neglect self care and our self esteem suffers because of it. We have to relearn how to do things for ourselves. You'll see posts from me in there that simply say "I shaved my legs today". It's winter and I'm single, I am the only person who is going to see my legs. But I only shaved my legs three or four times last year, I swear. It just makes you feel good inside and out when you take care of yourself, not for the sake of impressing someone, but just for you.
One thing that helped me with brain fog in the beginning was making to-do lists on my tablet and deleting items as I completed them. I was starting to learn that I could be productive on my own. I couldn't rely on just my memory and mentally saying here's what I have to do, now where do I start? I set aside a whole day and got up and got things done.