Welcome!
Hi, DancerKaz, and welcome to TP. I am sorry to hear about your mother. I've received lots of great advice, support, and information here on TP, both in current threads and reading through older ones, and hope you will find it helpful as well.
As I'm outside the UK, I'm not very good with knowing how your systems work, so I hope someone else here will pop in with the relevant information, but have you got her registered with a local GP, had an assessment, gotten PoA, all of that good stuff? I know there's a process you need to follow so you can get carers and funding and all that sort of thing; I'm just not sure what this is.
I do know that Age UK and the Alzheimer's Association and whatever you have locally, are all really good resources for you. In your area you might or might not have a day center/day care program, carers' support groups, a carers cafe, a singing for the brain group, dementia befrienders, programs offered through local community centers/groups/churches/charitable organisations/care homes. All of those are possible sources of help and information.
There are plenty of people here who have a PWD (person with dementia) living with them. You might find your way over to Ann's thread (So Bizzare!), as she documents caring for her MIL who lives with them, and see if there's anything there that resonates for you, or not, as you wish.
You may also find it helpful to find out more about dementia; there are some good fact sheets and resources online. It's a steep learning curve, but the more you understand, the more it may help you. Information is power (and about the only control any of us have over this terrible disease).
While your mother may be understandably resistant to having people come in, or going to day care, the advice here is that it's best to do this as soon as possible, to establish the routine, as even if help isn't needed right away, it very well may be soon.
You are absolutely right, you do need time to yourselves. Don't forget that you and your husband are important and have a right to your own lives. I have learnt this about dementia: it will eat as much time and energy as you throw at it. If you do not look after yourselves, you will not be able to look after your mum, and that won't help anybody.
Also, don't forget that in addition to having carers/companionship come in to be with your mother, that you can also hire other kinds of help: cleaning, gardening, repairs, that sort of thing. Or you can send out the laundry, decide never to iron again, get the groceries delivered, whatever helps in your situation. You may, at some point, need to free up some of your time from domestic duties, for other things (sleep, caring for your mother, walking the dogs, whatever you like).
Some people are able to convince the PWD that the paid carers are in need of the money, and therefore it's a kindness to "help them out" by letting them come to your house. Others say that the doctor ordered the help (it's always a good idea to shove the blame off on an absent authority figure, or anyone else, whenever possible), or that it's a free service, or whatever is enough to get a foot in the door. Often there is resistance upfront to the idea, but the PWD is able to get used to carers, so you also might just try not asking your mother, and, depending on her memory and level of delusions on any given day, I might not say anything in advance. I don't mean that to sound cold or uncaring, just practical and expedient.
You have undertaken a massive and important job and I take my hat off to you. Not everyone can take in a family member with dementia, for a variety of reasons, and of course it's very hard work. Even with you and your husband living there, you are basically on call 24/7, 365 days a year. That is bound to take a toll, so don't underestimate how hard it can be. The great thing about TP is that there are lots of other people who have been where you are and so there is plenty of advice and support available here. And don't hesitate to tell your GP what is going on, and get help (and maybe a counseling referral) if you need it.
I also previously lived a hundred miles from my mother and trying to manage things long-distance (without a diagnosis) was awful and near about killed me. I'm glad you have relief from the long distance worries, and the drives, and all the other things that are so difficult to do from far away.
I do hope that being in a stable environment with family will help to calm your mother and reduce the distress, anxiety, and general upset.
Don't hesitate to ask questions, seek advice, or just come here to vent. TP has helped me keep my sanity. I hope it's helpful for you as well.
Best wishes to you all.