Dave's ESL Cafe's Student Discussion Forums

[missdaredevil]

I think we've shot through happiness as one does in ypomania and come out the other end.

Australia leave suddenly: to leave a place, usually abruptly ( informal )

Thanks

[pugachevV]

To shoot through is Australian slang; it means to escape, depart or abscond. I have heard it used to say someone has died. "Bill's shot through."
I think in the example you give, it may mean, passed quickly through
happiness, as is common in bipolar disorders, and is now into the depressed phase of it.