Caring for my grandma and mother. Any words of encouragemnt for me?

I'm caring for my grandma and my mother now. Before for those who remember me, I was just caring for my now 86 year old grandma with the help of my mother. My mother is now diagnosed with a terminal cancer and been given the time frame of 12 weeks to a year to live. I'm dealing with the shock of that news plus since my mom is needing care, I'm juggling work (with caregivers coming to help my grandma during my work hours so far), caring for a house of four (my dad, mom, grandma and me) and caring for my grandma and mom. It's trying. I feel impatient and angry a lot. I know it's normal to deal with such emotions but it's making it harder to care for my grandma. She's needing care 24/7, my mom is barely getting out of bed due to the pain and the lack of energy she is having. I'm looking for inspiration and encouragement somewhere.

My mom is debating putting grandma in a home because honestly I'm at my wits end. And I know it's not her fault. I know it's not fair. My mom and I agreed to care for her knowing that when it got tough, the other would step in. It was working but that's all changed.

My grandma has dementia so she's constantly doing things not realizing her age and I feel frustrated when she does. Then I feel bad for feeling frustrated when it is not her fault. I know it's going to get worse. Mom is going to be harder to care for as right now she's just spending her days in bed and eventually it will get to the point of where its more than that. Grandma is needing more care as she is having more accidents and forgetting where she is and where she's going. She is dependent on mom so I can't imagine what she will be like when she's gone. So anyone has any words of encouragement for me? Please?