Welcome to FT! ^
With most domestic airlines, you get one carryon and one "personal item," with the personal item a laptop bag OR purse OR backpack.
For most of us on FT that means that largest rolling suitcase allowed in the overhead bins and a laptop bag that goes underneath the seat in front of you. It does not mean: one rollaboard + one laptop bag + one shoulder bag + two shopping bags from Bloomingdale's.
Enjoy your flight, especially your thimble of soda and peanut.