Probably it's depression, because depressed people see life more negatively, and I dare say, accurately, than those who don't have depression. But I think my depression is not existential in nature but rather consequential to other issues. At one hand, socializing with others bother me emotionally (I'm socially awkward/anxious, sensitive and despise fake conversations and don't like small talks) and intellectually (I don't get along with other people's way of thinking), but on the other hand, I crave the basic things other crave, like genuine connection, intimacy and love. The feelings of both socializing and being lonely are overwhelming to me. So, I feel I'm torn. Feeling isolated and the loneliness is the cause of my depression, at least in my analysis.

Being intelligent isn't necessarily something good, especially if it's way above average. Many great people (in the intellectual sense) were actually not happy in life if not miserable. I don't wish to be intelligent but alone and miserable.