in the club (或 the pudding club)

(Brit. informal)pregnant

(英，非正式)懷孕的

join the club

[in imperative](informal, often humorous)used as an observation that someone else is in a similar difficult or unwelcome situation to oneself

(非正式，常幽默)不光是你一人，我也一樣

if you're confused, join the club!.

如果你感到困惑，我也一樣！。