Why would this be? It is obvious the existentially complicated things create anxiety.

Is that obvious? Or do the immediate, simple things - I have to see everyone at school tomorrow and they all think [something bad about me] - create anxiety more? I think it's probably easier to distract yourself from "ice is going to melt into the ocean and kill a bunch of people eventually" than from "people are having fun and didn't invite me RIGHT NOW"

Learned helplessness is a thing that leads to depression, and depression in turns demotivates and deepens sense of helplessness. They do mutually reinforce, and either could be the starting point.