I also live alone and have little energy for housework. Here are a few things that have helped me. For meals, I often use my crock pot. Even if you're not feeling well, you can throw in just a few things (make it up) and have a nice cooked meal that will last a few days.
For housework, I've tried a few "hacks." Vacuuming can be difficult, so I bought a roomba. I also bought a cordless vacuum I love. I can usually do the house on a charge if I'm quick (or split it between 2 days). It's a hassle to keep plugging and unplugging. To make kitchen/bathrooms look nicer longer, I wipe around with a paper towel (or towel) every time I use. The sink looks nice for 1-2 weeks. I also "donwsized" my clutter. The less I have, the fewer things I have to move when I clean. Not sure your budget, but maybe every few months hire someone for an hour or two (?).
Finally, I asked myself what needs to be clean for me to feel like the "house is clean?" Or to put it another way, "What makes me feel like the house is dirty and messy?" Basically, it's the kitchen, bathroom, cat's litter box, and walking past an unmade bed. So I take the trash out and on weekends and (if I'm not sick) I make the bed, then check the kitchen and bathroom. If that's done, the vacuuming and other chores can wait. I wish you the best.