Alcohol caused a long list of problems in my brain. I can't tell you why or how but I can tell you it definitely did. And it took a while for things to get better when I quit drinking, but they did improve over time. Our minds are very adaptable, and can even overcome significant physiological damage over time.
It's also very possible that you have clinical depression or some other condition that requires treatment. I know I had several issues I had to work out once I quit drinking - simply ceasing to drink did not solve them all.
It's also fair to say that most psychological problems cannot be solved while you are actively drinking, or at least it's much more difficult to solve them.