Singleness really does equal invisibility sometimes. When your well-meaning friends say things which only make you feel worse, and ask again "why not me God?" That irrational fear you experience because you don't know how else to be faithful, or to do God's will. And what am I doing wrong to still be here?
So, next time you talk with your single friends, keep in mind that they too have dreams and aspirations and fears and hurts, and make sure your words are wise and considerate.