Empathy for Caregivers; what do we do when people can't or won't acknowledge our challenges?

This may have already been discussed in various questions in the forum, but I really don't have a space to share my thoughts or feelings about the challenges of being the primary caregiver for my mother. My mother, 77, began to physically and cognitively decline about three years ago. Already diagnosed with diabetes, cirrhosis of the liver (fatty liver disease), a stomach ulcer, and anemia, she developed a UTI infection. She went through a state of delirium for almost a month. When she was released from rehab, she contracted the flu and developed shingles. She was hospitalized several times over a period of several months. She hasn't been the same since. After her hospitalizations, she was later diagnosed with congestive heart failure and macular degeneration. As a result of the chronic conditions and prior mental health challenges, she does have cognitive impairment. She has good days and bad days. Since my sister lives 15 to 16 hours away from my mother with me living only one hour away from my mother, I took on the task of being the primary caregiver. Needless to say, it has been a very hard, lonely road. Knowing that many individuals have their own challenges in life, I have avoided dumping my own frustrations and challenges of caregiving upon individuals. However, there are times, especially when the challenges feel extremely overwhelming, that I have confided in certain individuals. While some individuals have been supportive, most make remarks such as "at least your mother is still alive," "you should feel grateful that she's still alive," "I wish my mother could still call me." When I hear such comments, I try to empathize with these individuals. I know that many people miss their loved ones. I also know that what they're saying is coming from a good place. However, their remarks do come with a tone of condemnation, that I should feel ashamed or guilty for voicing frustrations related to caregiving. I love my mother very much. She is my hero. I have made very real sacrifices to make my mother happy and comfortable. It has been painful to witness her decline. Even though it has been painful, I'm always there, supporting her 100%. I know that most of that support is invisible to many people. Just recently, my mother called me 21 times within a span of 24 hours regarding a small change with her diabetic meter and lancet. I picked up the phone every time she called. She had several meltdowns. She gets hung up on things now, fixating and ruminating. Her confusion certainly doesn't help. While trying to ease her anxiety, worry, and fear, I was working, teaching to be more precise. It's the last week before spring break, which means everything is much more challenging. Again, when I expressed how tired I was, a friend stated, "what I would give for my mother to be back alive and call me 21 times." All I said was that I was tired. As caregivers, what do we do when people can't or won't empathize or acknowledge our challenges? What do we do when people attempt to silence us by shutting down the conversation or reminding us of our 'place'? How do we express our own anxieties, fears, frustrations, concerns if we can't share them in the places/spaces we most frequent? How do we even navigate everyday conversations with coworkers, colleagues, friends, or family members? Are we just supposed to put our nose down, shut up, avoid our own physical and emotional challenges, and continuously guilt-trip ourselves for our 'ungratefulness'? I know that these questions are quite open with no clear or defining answers. I just really wonder how I'm going to be able to do all of this if I'm going to be silenced even when I just say that "I'm tired."