No matter how much my partner and I do for my Mum, it seems like it's never enough. She is in a care home and has some mental health issues and her mobility is limited. She doesn't have Dementia. She's asks for things every time we visit, which is 4 times a week. We are both shift workers, and I am presently recovering from leg surgery with an infection in the wound. Also having physical therapy for the other ankle and my back, so my own mobility at the moment is not great. When we bring her the things she's asked for...we don't get any sign of gratefulness. No thank you, nothing. She admits that she only cares what's happening with her. I'm finding myself not wanting to visit her and I feel guilty.
If she doesn't have dementia then you can tell her that you are not willing to do anything for her until she starts expressing gratitude.
Having guilt isn't a gage whether you are a good person or decent. It means that you feel like you are doing something wrong. Setting boundaries and enforcing them is acceptable and important for your wellbeing.
If your mom isn't willing to show gratitude or appreciation then it is okay to not comply with her demands. You are a grown up and you can make your own choices.
By the way, your situation is all to common. Parents thinking that their adult offspring have some obligation to jump through hoops. Nope!
The end.
It's what I do with my own mother, it preserves MY sanity, and she's no worse the wear for it. The end of life process can go on for many, many years, and things tend to get worse & worse with the passage of time. It's time to think about YOUR needs now, and not just your mom's. I read somewhere that 40% of caregivers wind up passing BEFORE their elderly loved ones.
Best of luck!