The speaker of "Better" admits they aren't sure whether they've really improved. They keep saying they're better, without knowing if it's true or a lie, and they choose to hold on to the feeling anyway, even if it turns out to be borrowed time.
The mood is fragile and quietly tired. Hope and doubt sit side by side in almost every stanza. One moment things look brighter, the next the speaker just wants to lie down and cry. Night and the moon bring back the thoughts they always fight, which suggests the good days can slip away when they're alone.
What stands out is the idea in the fifth stanza: maybe setbacks make the good days count more. That's a gentle, stubborn kind of hope. The ending, with "I'm always fine" in brackets, feels like a mask. The speaker keeps up the act and waits, quietly, for a better that lasts.