I disagree with the first part of John's post.
(1) Fatigue is caused by feeling fatigued.
Weariness comes from quitting.
It reads like a smarandanche tautology:
Being tired is a feeling, it'll pass. But if you act on that feeling, say quit, and continue that pattern you will eventually become weary;i.e., you will eventually become reluctant to take on other e.g., jobs, assignments, etc. "Weariness comes from quitting"; Paradox: It's not the other way around: quitting comes from weariness.
In addition to John's post,
(2) "a losing proposition I had been" means, s/he wasn't worth consideration by others.
To propose, a verb, means to put forth something for consideration by others. Proposition, a noun, refers to the thing that was put forth for consideration.
Hope that helps.