How do you take 24 care hour of your mother for 300 days?

I was always pretty much invisible to my mother growing up, she did just about everything she could to destroy my self-esteem from day one. Everything my siblings did was fabulous but I was just there. My sister lives out of the country and my brother died, so it's quite ironic I became her caregiver. She is and always has been a very controlling and fear-based person who will not cooperate with anything reasonable in any aspect of life She is a negative enabler of other members of the family and puts herself at risk of running out of money to die at home but in her eyes they are perfect. I do everything with her and for her she is bed bound with end-stage metastasized breast cancer. Just to give you an idea of her control issues, she found out four years before, that she had a lump in her breast, this was before my father died, my sister had flown in and she had obviously been hiding something because she was getting weaker and in pain. He forced her to go to the doctor with us and found out there she's known for over 4 years she said she didn't want to worry anyone when the fact is she didn't want anyone to tell her what to do. So I had to completely change my life, move in with her she is unbelievably demanding and controlling often I don't get out of the house for weeks. She talks badly about me behind my back when I take care of her 24 hours a day I am kind patient and do my best to meet all her constant demands for 300 days now. She controls everything because she's mentally competent, if you want to call it that, and does her best to control and manipulate me. I was independent since I was 17 and achieved many great things, including raising two incredible children they are the love of my life. I made sure from day one I did everything exactly opposite of how she did- treat them with respect, listen to their feelings and concerns always and tried to teach them anything was possible and to follow their passions. They have, I don't take the credit as I was just there guide and they ultimately made the decisions to make their lives what they are, but I am so grateful to have been a part of that. I am 57 years old, my whole life is on hold and I'm not getting any younger as well as severe injury-related pain. I saw someone else say I can deal with all the appointments with hospice Elder Services Den excetera excetera excetera and being responsible for everything to run the house. It's her attitude manipulation toward me that makes it unbearable. After the first four months I had a minor heart attack, have severe anxiety, insomnia and the list goes on. After realizing I was going to have a breakdown, I began finding myself again, by detaching from the manipulation. I have always had God my friend, Jesus my teacher, read the lessons of Buddha, practice grounding myself and replacing every negative thought that sneaks in by 3 positive thoughts. I visualized my future and know that even though it all looks and possible to survive after this especially financially, everything is going to be okay and my start at a new life will begin. I have been divorced for 20 years and lived independently with the love of my friends and the love of life. I don't talk much about it except to my sister and sometimes my daughter who is also my best friend and they offer so much encouragement but they're not living it. I've been through a lot in my life nothing has ever made me feel that I was fighting for my life everyday.