de·pres·sion
/dəˈpreSH(ə)n/
Noun
feelings of severe despondency and dejection.
/////
America does very well in hiding his depression from the other nations, using his hero persona to mask the real him. The mess he was and what an utter failure he felt like. The mask begins to slip, revealing a tiny bit of the person he tries so hard to forget. When the other nations take notice, they start to suspect that their superpower isn't as happy as he seems.
...
Book 1 of the Mask series
(Book 2 being made)