How do I pay for the help that I so desperately need with Mom?

My mother is living in my home with my new spouse. I AM EXHAUSTED! I work as a caregiver privately then get to care for Mom after. I am finally after 18 months reaching out for help. I am the youngest of 5 girls so you would think I have plenty of help. NOPE. This is after the oldest took my mom for almost everything my dear dad left her with, we are talkin A LOT. I don't have the strength physically or emotionally to start that battle. But all I see when I look at her is saying "I get all this because Sam (my dad) and I made a deal that I care for Mom." Well 8 years later, I am caring for Mom, but without the resources. In the last 18 months my sisters have taken her overnight 4x. When Mom is gone all I can do is sleep. I have many health issues myself and was diagnosed with COPD yesterday. I just can't do this much longer. But no one seems to hear me because I do still work 6 hours a day away from home while my 22 year daughter watches Mom. My daughter is moving out very soon. Now who can help? All I get from anyone is excuses as to why they can't help. I promised Mom I wouldn't put her in a home, but I may not have a choice. I have called a couple advisors, but I am told Mom's SS will not cover the cost. Also I can not seem to get straight answers from my sisters about finances for the past 5 years. Mediacid wants that information. I am so sorry if I seem to be rambling on, but I JUST CAN'T ANYMORE. My brain is jumbled like scrambled eggs. Any advice would help. Screaming NOW.