How does Fitzerald show us that Gatsby is nervous about meeting Daisy?

It rains on the day that Gatsby and Daisy are to meet, and Gatsby becomes extremely apprehensive. The meeting takes place at Nick's house and, initially, their conversation is stilted and awkward. They are all inexplicably embarrassed; when Gatsby clumsily knocks over a clock, Nick tells him that he's behaving like a little boy.

Source

It's raining, and yet Gatsby sends someone to take care of Nick's lawn. Gatsby send over a "greenhouse" of flowers to put out, he's pale from a sleepless night, and he stresses over desserts at the deli. And this all happens before daisy arrives!