Looking back over your posts It's pretty obvious that you have always felt the welfare of others to be something you are responsible for. Both with family and employment. It shows a giving nature and true it is appropriate to look after others, but you are not a bottomless well of strenght and tolerance any more than any other human being
One of the worst things of course is that one gets to be not appreciated, and others assume they can make demands, and that their wants are more important than yours. Over time this really erodes one's feeling of worth and confidence (quite unjustly, but it is sadly human nature to feel that way:(
One can end up feeling trapped.
I'm unsure as to your current circumstances, and do not know if you have obligations you feel for others at the moment or are alone.
Perhaps you might like to say a little more about that. I"m not sure if you are still looking after your mum (I really apologize if I've missed something important you said about her)
I do know you have been invaded by siblings and thier partners and children and that turns a home in to a sort of barracks, with no real mental or physical space you can simply relax in and be yourself.
If you were to have your own space, time and no pressing demands do you have a pet dream? Or even just a vague idea, of how you might like to spend your time?
I hope you come back and we can talk more