Bless you Dimpsy, and thank you for your deep empathetic response. again, a lump in my throat at the care being sent out on this forum.What lovely people carers are and what a burden to carry; never mind all the sheer physical effort of caring for a PWD, sometimes that is easier to bear then the emotional side. Decision making, organising and then whatever choices we make, in creep the doubts and the 'what ifs' and 'should I's'.
Compare the time you spend worrying about your mum and her situation, to the time thinking about your own life and I guarantee you come a poor second; oh, the selfishness of dementia, its ripples spread far and wide.
Reading your rant, your concern is entirely for your mum, pity for mum's plight, no self pity for you that I can see.
You've given your best - and more - to your mum and life will settle for her, she is safe and cared for which should bring comfort to you, except it isn't, is it? You are torturing yourself because mum wants to go home.
You have answered part of that problem already by recognising that it's probably her childhood she wants to go back to. It's impossible not to get upset when your mum is so distressed and it's plain to see that it is tearing you apart. If you search through this forum you will see how other people have dealt with the separation issue; how to extricate yourself from visiting mum with the least possible upset for either of you.
We're human with frailties and sometimes a good cry is the only way to go, then wipe your tears and feel proud of yourself for being such a caring daughter, your mum does.