If you still want to move back when you're feeling good, you should pitch this to your employer with it being a negotiation in mind. Tell your employer that you've done your best to stick it out in the city, but that you just have too many close friends and family that live far away and you want to be near them. Then tell your employer that you are looking at alternatives to make it work, like doing contract work, but tell them that you would love it if you could work remotely for them.
Make it clear that you've made your decision to move back and that it's happening soon. If your employer senses that this is a gambit to get out of the office they'll probably call your bluff. Good luck!