feel on top of the world, be on top of the worldexprexpression: Prepositional phrase, adverbial phrase, or other phrase or expression--for example, "behind the times," "on your own."
figurative (be very happy)
心满意足 xīn mǎn yì zú
兴高采烈 xìng gāo cǎi liè
欣喜若狂 xīn xǐ ruò kuáng
The day his daughter was born, the new father felt on top of the world.