Melanie

“I'm tired of living unable to love anyone. I don't have a single friend - not one. And, worst of all, I can't even love myself. Why is that? Why can't I love myself? It's because I can't love anyone else. A person learns how to love himself through the simple acts of loving and being loved by someone else. Do you understand what I am saying? A person who is incapable of loving another cannot properly love himself.”
― Haruki Murakami, 1Q84

“How could I have been so ignorant? she thinks. So stupid, so unseeing, so given over to carelessness. But without such ignorance, such carelessness, how could we live? If you knew what was going to happen, if you knew everything that was going to happen next—if you knew in advance the consequences of your own actions—you'd be doomed. You'd be as ruined as God. You'd be a stone. You'd never eat or drink or laugh or get out of bed in the morning. You'd never love anyone, ever again. You'd never dare to.”
― Margaret Atwood, The Blind Assassin

“I'm lonely. And I'm lonely in some horribly deep way and for a flash of an instant, I can see just how lonely, and how deep this feeling runs. And it scares the shit out of me to be this lonely because it seems catastrophic.”
― Augusten Burroughs, Dry

“Toska - noun /ˈtō-skə/ - Russian word roughly translated as sadness, melancholia, lugubriousness.

"No single word in English renders all the shades of toska. At its deepest and most painful, it is a sensation of great spiritual anguish, often without any specific cause. At less morbid levels it is a dull ache of the soul, a longing with nothing to long for, a sick pining, a vague restlessness, mental throes, yearning. In particular cases it may be the desire for somebody of something specific, nostalgia, love-sickness. At the lowest level it grades into ennui, boredom.”
― Vladimir Nabokov