The speaker begins with a plain admission: they got what they wanted, and they still feel unhappy. That sounds like a contradiction, and the poem seems to know it. The title, "Do I Need Happiness?", turns the problem into a question, as if the speaker is no longer sure that happiness is something they can or should chase.
The second stanza pushes the idea further. Even if they had "all the love on earth," their thoughts still wouldn't make them smile. The trouble, then, doesn't seem to come from what is missing in the world around them. It sits inside their own mind, in the way they think. Judging by the wording, the speaker feels stuck, aware that outside things can't fix it.
The mood is quiet, weary, and a little numb. The short lines and flat tone make the sadness feel calm rather than dramatic, which makes it more unsettling.