Msida, having just read the previous post that you made about why you moved in the first place, I can't help feeling that the best thing you can do, is to try and look forward, and forget about going back to your old home. The reason I say this, is that even if you could go back, you still won't be happy there, as you're clearly grieving, and as many of us Grans know, that's a long hard road to tread.
Are you physically able? If so, can I suggest that however low you may be feeling, you make the effort to go out for a minimum 20 minute walk each day. I used to suffer dreadfully from depression, and found that the more I exercised, the better I felt. Do you have any hobbies? If so, now is the time to get back to them. Concentrate on doing things that will pass the time, and keep your mind occupied, whether it be a crossword, needlework, or even a jigsaw puzzle, which you can even download for free online, so that you're not dwelling on what you see as the mistake of moving. You mention family and friends, have you pushed them away since you lost your husband? If so, now would be a good time to reach out. Invite them to see your new home. I believe that you're living in a flat, do you see people of a similar age group, coming and going? If so, watch to find out which flat they live in, and then pop a note through the door, saying that you're a new tenant, have seen them about, and wondered whether they might like to join you for a coffee, giving a day and time, followed by, 'if that isn't convenient, but you'd still like to meet up, do give me a call on ....... and we can arrange something to suit us both'.
I think ultimately what I'm saying, is that you are focusing all your energy on trying to move back, when really what you need, is to settle down, and catch your breath after all you've been through. I would also suggest having a chat with your new GP, (assuming you've moved far enough to have changed doctors), and explain how miserable you are. You will probably find that they will issue you with a mild antidepressant, which will, once it's had time to get to work, help you to see that things aren't all as bad as they seem right now, and you could also ask if there are any bereavement counsellors that you could see.
I hope that maybe some of what I've said might help change your direction of thought, and if you're feeling lonely and would just like to chat, do please feel free to private message me.
Wishing you all the very best and sending a bunch of
to brighten your day.