Hi Steve
Hi Steve - and welcome to TP. I hope it'll be as helpful to yoas it has been to me, and to many others.
I had a long period of being in much your situation - only child of someone living alone, except my Mum was a hundred miles away with the whole of London inbetween us - a three hour trip. I cant take away the exhaustion and the stress, but I can at least say that there are many, many of us on TP who've experienced and will aways be there to listen (if that's the right word for the Web). This is a place when you can come online and let off steam if you need to - please don't feel you can't. We're all only human, and sometimes that's exactly what you need to do.
A few things to add to what others have said: if your Mum, like many, uses hand and face creams, try one with some lavender oil in it. Not only will she smell nice, but the lavender s very calming and soothing. (A nice tip passed onto me on TP, and it seemed to help). Does your Mum also have friends and neighbours around her? (I was lucky in that Mum still lived in the house I grew up in, so I knew most of them.) Keep in close contact with them - if you can cultivate half a dozen, they can take it turns a couple of times of a week to give you a night off if they'd be ok to pop in and see your Mum for a bit so she gets some company - even if it's just a cuppa and a chat. My Mum's neighbours were my eyes on the ground when I couldn't be there, and I was able to get them in touch with the CPN so they could raise the alarm if they were particularly worried about anything.
And another thing I learned from TP: you have to shoulder up to what someone here christened TE Guilt Monster. Of course you care about your Mum and you're worried about her, but - as you've already said - it's wearing you out/down. Of course it is - you're not a machine or a superman, and you need respite too. More importantly, if you don't look after yourself you won't be able to look afer her properly when you are with her. Most of the help you can get you have to accept you're going to have to ask for, demand or cajole/encourage/charm out of others, but don't try to cope with everything - it's not the way forward for you or for her.
Please keep posting and letting everyone know how you're getting on.