I am not single, but I want to answer anyways.
In highschool, I used to be afraid to be seen alone eating lunch. I used to be a complete loner and I was really ashamed of myself.
I am still a loner, but I think I like it. I am enjoying the aloneless, there is so much more time to reflect and focus on my consciousness,phsyical and mental being. I am not good with alot of people, I tend to shift my attention to pleasing others, wanting to be accepted by others, and living up to certian personally unachievabe standard, I found that being alone protect me from trying to be someone else, to have expectation or to face rejection.