@placidWater4378, I doubt that this feeling is uncommon, but that doesn't mean it is the way it needs to be. Sometimes, the work might be thankless, and perhaps your elderly person is grumpy, cranky, ungrateful. So you may need to look inside yourself for confidence and a better feeling. Knowing that you are doing the right thing by your elderly parent is something to be proud of. Knowing how to care for them, and set boundaries to protect yourself, is difficult, but not impossible.
Do you have a schedule that works for you, with times for rest and relaxation away from the caregiving? If not, you may need to firmly ask other families to at least step up and give you some breaks. Or perhaps there is a local social services agency, or volunteer agency, that could provides respite caregivers.
Also, are you dealing with the difficulties brought on by dementia? That is a challenge. If you are able to learn to live with the person in their current reality, without arguing or trying to convince them of something, it might go better. Distracting them with music, simple art activities, or a short walk outdoors might help.
I hope any of this helps.