Loneliness

Noun: loneliness

1. The state of being alone in solitary isolation
2. Sadness resulting from being forsaken or abandoned
3. A disposition toward being alone

Yeah, it's true that one is most lonely in a crowd. I feel lonely when I hear laughter outside my door. I feel lonely in the presence of people who know so little about me. I feel lonely without anyone to talk to, without anyone I can have a proper conversation with. I am lonely because I don't like people.

I am lonely 1, 2 and 3.