Went through a similar dilemma a few months ago. Got a promotion that I knew would involve killer hours, making training difficult. Made a tough decision and took it. Generally am glad that I made the decision I made, but there are pros and cons for either choice.
A few things:
Fulfillment can come from anything you put your best effort into. When I was working a less demanding job, I was more passionate about running and the thought of investing anything less than my best into it was unthinkable. Now that I'm more immersed in my job, I care about my professional input more than I ever did. I'm still running competitively, but it feels less life or death. If I have bad workouts because I'm exhausted, it's not the end of the world.
I highly recommend moving closer to the new job. That was part of the deal I made for myself. I wanted to keep running and take the job so I used some of the extra $ to get a place within walking distance. It's totally overpriced and I'm not saving much $, but I'm young, building up a professional reputation and able to continue with the sport I love. That's enough for now. Would obviously be different if I had a family to support.
As for actually being able to do both at a high level, the jury's still out. My results have been less consistent since I took this job, but I've had some very good races. There are weeks where I feel like training is a nightmare and quitting is inevitable and weeks where I feel like I could keep up forever. But I know I'm a much more effective person in all facets of life if I have too much on my plate, rather than too little. Not everybody's like this. You'll have to figure out what environment is best for you.
It also helps that I don't plan on doing this forever (neither competitive running nor my current job). So I can think day-to-day without really dwelling on how demanding of a life it's become.
Ultimately, running is just a game but so is life. If it makes you happy, you'll find a way to keep up with it. But you don't have to be so absolutist as to pick running or working hard. If you take this job you'll force yourself to be extremely disciplined and learn a lot about yourself.