Are you earning more money with the promotion? If so, I say try to tough it out until you and your girlfriend move. Saving the extra money will definitely help in the long run. That said, if you aren’t earning anything more or much more, consider going back to your old position, that way you’re able to keep the job a little longer without going insane. I know what it’s like to work a job you loathe. If it starts wearing you down too much, get out of there as soon as possible. Your happiness should come before anything else. Good luck to you.