The speaker opens the poem with an image of total nothingness. No matter where she walks, she's only greeted by blank space. It's a powerful image because it gets across really quickly just how alone she feels. It's interesting, though, that despite all this emptiness, she still keeps moving. Could it be that she hopes that one day she won't be so alone? Does she keep walking in hopes that one day that blank space will be filled?
To stop—or perish—or advance— Alike indifferent— (4-5)
Well, this is depressing. The speaker now tells us that it doesn't matter whether she stops, goes forward, or dies. It's all the same to her; when you live in nothing but nothingness, nothing really matters. Could these intense feelings of loneliness be caused by the fact that she has nobody in her life—no friends, relatives, lovers—who'd care if she died? It sounds like the speaker needs to get on Meet Up stat.
I shut my eyes—and groped as well 'Twas lighter—to be Blind— (9-10)
Here, the speaker tells us that she also tried to crawl though the void with her eyes shut, and that things seemed a little brighter with her peepers closed. So all the emptiness around her made her feel so isolated that it was better to not even try to see it. We wonder if the speaker is saying that sometimes thinking about how alone we are is just so depressing that we need to hide from it a while. Sometimes the dark can be comforting (though we prefer to at least use our Adventure Time night light).