Love arrives here like sunlight inside an empty space. The speaker describes a hollow place within themselves that has been waiting for a hope they had forgotten, and then warmth floods in, spreading to their fingertips and almost splitting them open. All of that feeling points at one person, and the repeated "you, / you, / you" makes it sound both devoted and a little breathless, as if no other word will do.
The last lines turn darker. The speaker enjoys the glow but already knows it won't last, comparing themselves to Icarus, whose wings melted because he flew too close to the sun. Love and loss are tied together: the thing that fills the speaker is also what will undo them. The mood starts out tender and glowing, then slides into quiet dread, leaving the sense that this happiness is beautiful precisely because it is doomed.