Someone's posted this fic search before but the comment identifying it was deleted.
C/W: suicidal ideation
* Takes place after the bicycle ride. Bertie thinks that no one, including Jeeves, likes him
* Bertie goes back to London and puts his affairs in order and buys some laudanum
* Jeeves finds the pills and prevents Bertie from taking them
* Later they're in a park and a soldier who served under Bertie talks to him and it turns out he's actually a war hero
I've trawled through AO3 trying to find it but no luck. Hoping I'll have some success here. Thank you in advance!