My quarterly freak out on my family.

It's been three years now taking care of my mother, Most of the time its a pleasure, she is no problem at all. she has Alzheimer's, not as bad as a lot I have read about. I work all day and sit with her all night and weekends. I find it harder and harder to get her out of the house and when I am able it takes her well over 2 hours to get her ready. I had so many issues with her caregiver last week it left me in a very bad position. I'm so lucky to have the friends that I have, they bent over backwards trying to help me just be able to go to work. In a week moment I text my sister and told her that this was so unfair and she needed to step up and at least let me have a few months to recoup. I should have known better, her response was NO!!! I have seen how this has effected you over the last several years, your a mess and I refuse to put myself through any of that. She does absolutely nothing to help and I have no one else except for the wonderful circle of friends that I have but they are running out of time as well with there jobs. I'm so sick of this, I did finally tell my sister that I could no longer talk to her and I felt no obligation to tell her anything, she wants to sit up there have me and my husband do everything (he travels) but pretends to everyone (cousins and family) that we are doing all this together. before I told her to not contact me we were arguing about something and she had the nerve to tell me that she really did not give a ____. Mom's 5 year look back on her trust account would be up in 2 years. So I see she has just been sitting there counting the days until she thinks she can put her in a home and take everything. This sickens me. My husband knew how upset I was and even told me that if anything happened to me that he would make sure he would take care of Mom. My friends are worried that I'm going to have a heart attack or stroke. The caregiver became very ill last week, of course no fault of hers and was off for a week and a half, it threw me into so much stress just trying to cover the shifts that I was unable to get out of bed all weekend, had to cancel Easter dinner because I was down and sorry to say taking volume all weekend. I'm at my wits end not because I don't want to take care of my mom but because of the things my family says and the way the act. I'm so disgusted knowing that the day something happens to mom, they will show up and put on the tears and not be able to wait to sell and take everything she has, .It's 50/50 power of attorney. Of course my Mom and Dad never dreamed she would be this way nor did I. I guess I don't really have a question I just need to vent. I have to go away for a while just for a rest but how do I just get up and leave her with someone to step in and take care of her? I will worry the entire time and my family is not even willing to do that for me. Do any of you have these issues?