How does Q think that using his wish from the White Lady to go back to Earth is going to be any better than being in Fillory...?
He'll have the same heartbreak on Earth as he would there.
Really shitty wish in my opinion...

stupid wish he coulda got back with a number of other ways... he coulda at least cleaned the shit outa the wellspring or something

He just lost the love of his life after almost getting her back, by his own hands no less. Do you really think he was thinking clearly?