I have very few face to face relationships, and, yes, I feel lonely at times. I do enjoy my time by myself, sober, but I do at least engage with people at work, with my parents, and I'm going back to my first AA meeting in a couple years this morning. I am also considering getting started in some volunteer work outside the realm of recovery that will bring me greater self-esteem as well as connections to others face to face. As long as you are not isolating yourself from other people intentionally, I think it's natural to feel moments of feeling alone in your thoughts.