What is the poem "Let No Charitable Hope" saying?

The speaker of the poem has reached a stage in her life where she's able to reflect with some measure of wisdom on her experiences. She's now arrived at the conclusion that she's all alone in the world, and there's no point in getting hopeful about changing a condition into which she was born and in which she will die. As a woman, she also feels isolated in a male dominated society—even though she's no longer an "antelope," that is to say, prey to men's desires. Whatever enjoyment she gets out of life takes quite some effort, like getting blood from a stone. It's the only reminder of her humanity in a world in which she's all alone. Hers has been a life without fear. Each year brings with it the promise of hope, but it's really just an elaborate disguise, a mask at once "outrageous and austere." All the speaker can do is respond with a sarcastic, world-weary laugh.