Yes I know how you feel.
There are two parts of the day I dread, the first is the first glimpse of mum in the morning as she emerges from her bedroom. I can now tell from her body language, before I see her facial expression, what sort of a mood she is in and therefore how my day will pan out. I find myself on tenterhooks - if I see that it's going to be a 'bad' day I instantly feel drained it is so hard to put on my happy face smile and start a conversation.
The second part of the day I dread is sundowning time - at the 'other end of the day' often it's end to end complaints and accusations that I prefer my children's and husbands company above her company.
I don't know how I cope - as you say talking about it to those who have never experienced these things is impossible - they just don't get it. I have become hardened and find myself detatched form these more difficult parts of my days - sometimes I can feel myself "away" from mum - talking to myself saying"just smile", "don't say anything", "just focus on that tissue on the floor that I'm going to pick up in a minute" - thats how I cope.
Hope that your Friday is a good one (hope mine is too
!)