Chang 'e should regret stealing the elixir. What does this poem mean?

Chang 'e must regret stealing the elixir, but now it's cold at night.

Whole poem:

Chang 'e Tang Li Shangyin

The mica screen was dyed red by thick candles, and the Milky Way gradually tilted towards the morning star.

Chang 'e, I must regret eating the elixir, and now I am alone, in the blue sky, singing every night.

translate

The mica screen reveals the deep light and shadow of the candle, the milky way gradually falls and the morning star disappears. Chang 'e must regret stealing the elixir, but now it's cold at night.