Stung - I have been struggling with much the same.
I had always been told that your 40's were great years free of the insecurities and drama of your 20's and 30's. I vote it the worst decade of my life. I wouldn't mind going back to my biggest problem being that I spent my bill money on a new pair of shoes.
I don't get told "God doesn't put more on you than you can handle" though I know that quote and did think it was in the Bible. I get told often "that which doesn't kill you makes you stronger". Puh-lease. The past two years in particular have just sucked. Both of my parents have been critically ill for 15 months, and I opened a new business at the same time with a lousy excuse of a human being.
As of late I find myself daydreaming of handing back all responsibilities I have in life, house, business, parents, husband, and just running away. It has given me perspective why people become homeless and/or become suicidal. I am neither of those things - yet I get why life becomes so overwhelming and tiresome that one would just give up.
I am spending more time on my relationship with God whom I always believed in, but didn't spend much time with. Perhaps that is the purpose of all this. I think what gets me through is that somewhere inside me I believe it will get better because I don't see a lot of room for it getting much worse. I do have faith that has not left me. I have compartmentalized my life into facets rather than looking at the whole. The whole has a black cloud over it yet the facets have areas of joy and happiness.
I do think I have the ability to make things better and I am trying. Its very hard when many days the only thing I want to do is stick my head in the sand and pretend for a day that everything is ok. It doesn't seem like that would be a bad thing to do for a day but then the day turns into dayS and its worse than before. The business I can control - the parents are a situation similar to yours with RAH that I have no control over rather feel like I am an aimless ball just rolling around and waiting to see what the day or week will bring. I begin my day at 630 looking at my phone to see if anyone is in the hospital or if an emergency has occurred. It sucks.
Anyway I will be saying some prayers for you that this period of life will make a turn because I believe it will. Get your rest - most important. Stress on top of no sleep and exhaustion is a bad cocktail.
Hoping things get better soon.