I don't want to take care of my mother anymore but I don't want to put her in a home. What can I do?

I have been taking care of my mother solo for more than five years now. I live with her in her home and have to do everything for her as she is no longer capable of caring for herself. She, however, can use the toilet alone and without help but everything else is left up to me. I wait on her all day long up until her bed time and then she stays up much later than I do, so I am forced to lie in my bed, eyes wide open waiting for her to call me to help her to bed. I am exhausted and extremely depressed. I would like to work part-time but she has made me feel guilty about leaving her for any length of time. I can not hire caregivers as her income is small and wouldn't cover what a caregiver would charge by the hour. Sometimes, I just get up before dawn and take a ride in my car to buy a cup of coffee and pray that I won't go insane. I have no social life, and no one to vent to when I really need to talk. I am thankful for this site as the stories I read here have given me hope to keep going for another day. I am a Christian and it is all I can do some days to just pray as I go about my chores taking care of her. My son lives here as well and has a 2 year old daughter who spends more than half of the time living in my mother's home with us. My son is a good father and helps around the house as much as he is able but complains if he has to wait on my mother. In addition to taking care of mom, I also help out with the baby. I feel like I am burning the candle at both ends. My brother and his wife will not accept any responsibility in helping me nor do I have any resources in the community to rely on. I am so very depressed even though I take pills for depression and an anti-anxiety pill. I wish I knew what to do. At times I feel like life is not worth living as each day is the same waiting on my mother and being made to feel guilty that I am not doing enough to help her. Thank you for letting me vent.