Alcoholism is lonely, too. It seemed fun to party with others but there always came a point where I was alone with my racing heart and racing thoughts and that godawful thirst that just would not be quenched. Fortunately, I didn't progress far in my alcoholism but I'm sure the end is lonely, too. In some cases, even the alcoholic's very own mind leaves them (Wernicke encephalopathy, final stages of liver and kidney disease).
I decided to concentrate on my own happiness as the first step. I did a free happiness course. I read Loretta Breuning's Meet Your Happy Chemicals. She also has videos explaining the concepts on YT. I read science-based self-help books about habits, will power and alcoholism. As a result, I became a better adjusted person. I'm truly happy.
The first few weeks are just tough. All the brain chemicals are in disarray and it takes a while for them to settle. I remember being unable to enjoy anything. However, I knew I needed to occupy my time and pointless ponderation led me astray in the past. So I got busy. I learned, I cleaned, I ate well and went for walks, I went to bed at a decent hour. Slowly, the fog lifted.