on top of the world
• happy and elated.
• "he was interested in her and she felt on top of the world"
on top of
• on the highest point or uppermost surface of.
• "a town perched on top of a hill"
• in command or control of.
• "he couldn't get on top of his work"
• in addition to.
• "on top of everything else he's a brilliant linguist"
• in close proximity to.
• "we all lived on top of each other"