I feel this. I think loneliness has been the principle feeling in my life forever, whether I'm with people very different to myself or like-minded. Lack of connection == lack of purpose, and that makes every action more difficult.

Piers Steel researches motivation and has a book called "The Procrastination Equation". In the book, motivation is modelled as Motivation = (Expectedness * Value) / (Impulse * Delay). In his academic papers, it's rendered as:

Utilityᵢ = (Eᵢ Vᵢ) / (Γᵢ D)

That is, the perceived utility of any action increases with the expectancy that one will be able to finish it, and the perceived value of the end result, and is reduced by a person's inclination to be impulsive or distracted and the end goal's distance from the present.

How can any action have utility if someone has no place in the world? As a social species, our purpose is largely defined socially. When you're going solo, it's hard to get a sense of value of a given action.