OP ignore all the comments saying you're negative or have a personality disorder. Most people on here are literally mad and can't differentiate between somebody who needs a kick up the arse for a problem of their own making and somebody who has had life sort of happen around them.
I have moved a lot in my life, loads in fact. I always enjoyed house moves. Never found it scary or upsetting etc. around the other things in life I built a house, from scratch, a labour of love. I spent months their in the summer. It's mostly off-grid but still beautiful and I love that. Anyway, I hadn't bitten the bullet and moved into it, I am not sure why but I think the idea felt a bit like retiring. Moving away from the towns it's usually travel between and trading my old life in for the new one I'd spent years building.
When it went down I went into some kind of shock lol. I was non verbal for a few days just yes and no to people. It wasn't the move, lots of people told me moving was the most stressful thing etc but I'd moved home obout 10 times before without batting an eyelid, so I knew it wasn't that I just smiled and agreed.
It took me a long while to process the decision and suddenly from nowhere me and my partner had arguments. I'm not even sure what about, but it has never happened before. I am sure I was responding differently to usual but I wasn't being unfair or cruel, yes somehow seeing eye to eye went out of the window. (It's fine now btw).
I get it and I can't explain it either, it's a sort of sorrow at your old life being over, horror at the instability of the future and feeling trapped. As though you have made your bed and now you have to lay in it. Even if it's a perfectly lovely bed you made.
Take a step back, you're emotionally caught up in the micro moments and the past. You need to look at it from a different view, you will adjust you just need to let yourself. You will struggle while you're still hung up on wanting to move back, if you think that desire will always be there then shelf it for a set time. Tell yourself you will look at moving back again in 4 years but until then you will make it work where you are. This kind of reframing can make you feel less stuck and also give you motives to built savings or makes plans for if you really do want to return to London. Once you have that notion shelved you will be able to think more clearly because it isn't happening right now. So what do you need in the now that will make you happy? Only you know that but you can start with small things, add in a few routines that are centred around you to help you structure your day, I find yoga and running extremely good for stress relief but if that okay your thing maybe try social groups, sports groups, a hobby, reading or something immersive as a bit of eacapism etc and make it a part of every single day.
Mentally, if you want to have any quality of life you need to build it all around you. Which means staying present and focussing on the now and near future. You won't achieve this hung up on could have/should haves.
Be careful with yourself, you've just gone through a rollercoaster of emotions and maybe even some kind of breakdown. Do things that make you feel more in control. This could be things that make you feel more independent eg finding your own friends, places etc there or it could be making the new house yours by changing bits. I'm not suggesting knocking walls down, but some light redecorating and buying some new bedding etc can make a room feel as though you have ownership of it. It's important to restore this balance and begin feeling like you belong. When I moved I suddenly felt like I was in somebody else's life. I'm not very attached to many people so I didn't have that to ground me. I spent time outside, in nature and that helped too. I made plans for the garden which I'd wanted to change for a while. I still haven't done them but having the plans was enough, it gave me a sense ownership and something I intended to do.
Maybe explain to your partner that you need some kindness right now, but he doesn't have to understand. He won't be able to it's diffixult, look at the replies on here, most people don't get it because they haven't experienced it.
For what it's worth I'm fine now but it lasted bloody ages to feel better. I didn't even have a "reason" and I love my house so it's particularly bonkers.
Give your relationship a chance after you have dealt with this first. You don't want to lose somebody you love, if the last 17 years before now have been great. I know lots of couples who have gone through a bad year where they didn't see eye to eye or a stressful event took it's toll on the relationship. It doesn't have to be the end just work on your own feelings for now before bringing it back to your husband, he can't fix these things for you.