It feels like you are being very hard on yourself.
The situation seems overwhelming!
You have loved ones needing a lot of help. Yet, maybe you cannot sanely provide all of the help they need? Maybe nobody could do so?
This situations seems like one for a "team" of people as caretakers/helpers.
Please do step back, regain perspective and take good care of yourself!
Do you have adequate support in place?
Do you see a therapist?
Is it possible to get your family members' respective doctors involved to write referrals for help from agencies like "visiting nurses," occupational therapy, others?
Any one person would feel overwhelmed with what little you have reported here.
You have to care for yourself first and foremost!

WC