You're taking care of everyone but yourself. You're not alone. But I hope you can find time for what you WANT and not just what you SHOULD DO.
I do crossword puzzles and similar things (I get those variety puzzle books in the magazine aisle of the supermarket every so often). I remind myself that stress reduction and mental games are good for keeping cognitive functioning especially later in life.
I work out in a class 3 times a week - it's social and affirming, and we've become friends, holding pot luck dinners a few times a year. We figure, we can lift weights 3 times a week and therefore life a wine glass and a fork now and then! We sing some of the songs while working out - we're just goofballs about it - and it's really fun (we forget we're lifting weights). For example, if the instructor puts on oldies like "Breaking Up Is Hard To Do," we'll sing "working out is hard to do" instead. Anything silly that makes you laugh is a good thing!
I sing in a women's chorus that rehearses every week and then does concerts in nursing homes and memory care units 4 times in December and 4 times in May. We occasionally do another performance at a town celebration or arts festival. With my own mother now in the final stages of Alzheimer's, I see how important it is and how music can sometimes reach someone who's largely lost in that haze of dementia.
I garden a little - not enough to get exhausted or feel overburdened, but enough to enjoy the color and the pleasure of blooms. I have a large pot of mixed herbs on the porch - sometimes just cutting fresh rosemary or parsley to make a marinade for whatever I'm putting on the grill (potatoes, mixed vegetables, chicken....) makes me feel connected to nature and less tied to the supermarrket.
I read - a real book - before bed to be sure I get off the screens and the to-do lists. When I was overburdened with a child and 2 stepkids, I found goofy books like the Janet Evanovich series of "detective" type novels (Stephanie Plum is the heroine), but with absurd silliness. They aren't complicated and their largely implausible, which makes them fun. You might try something like that, with a character you can follow from book to book so you don't have to focus as much when you're tired!
I have a friend whose husband has Parkinson's and just drains her totally every day. She tries to do one thing for herself every day and she has a rule that she does not allow herself to feel guilty about what else she's not doing at that moment.
You know the flight attendant safety speech that goes, "Put the oxygen mask on yourself before assisting those around you"?? They know that, if you pass out from lack of oxygen, you're not good to your child in the next seat. Good advice for woking moms and everyone else too! Make that your at-home motto.