Nettle's poem captures a strange, quick shift in feeling: a woman is hurting, and then she is laughing. It opens with tears caused by pain, and the repeated "so intense" makes the hurt feel sharp and hard to escape. Her question, "Why the pain, why oh why?", sounds like a cry of frustration, as if she wants an explanation and doesn't get one.
Then something unexpected happens. Amusement "rushes through her," and laughter shakes her body. The tears don't stop, but they change their meaning, becoming "the tears of laughter." The final lines give the laughter a bolder role: it mocks the pain, almost like a way of striking back.
The mood is mixed, a little raw but also lively and defiant. The poem seems to suggest that laughter can sit right beside suffering and take some of its power away, without pretending the pain was never there. The closing repetition of "so intense" shows it still matters.