About the only useful part of this response is: I feel for you. I understand what you're going through, and I'm going to try and convince you to stick with it.

The rest of this: well, take it or leave it.

Sounds like you've managed to coincide two bad things in one go: a bad place in your career, and a bad place in your relationship. You've ended up with a double-whammy, so it's hit you hard.

From (limited) experience, I'd say let the relationship thing sort itself out. I know how it feels now: and it'll take 6 months before you wake up and go through the day, and then realise that you didn't think about it all day. That's when you know you're over it. Until then, just accept it. There are no shortcuts.

Meanwhile, focus on the job. It's the thing you CAN change. If you don't like it, change it. Maybe, even if it's "ok"... change it anyway. You need something that will distract, excite and occupy you for the next 6 months.

That's what I did anyway (also from the UK, also sporting a beard and feeding a cat). Change the career if you need to, because it's easier. Go and do something that makes you happy, for short-term (and long-term) happiness. The rest will sort itself out.

just my 2p