If you've bought all the upgrades, you can turn off individual toppings if they're too much!
Also the sticker that makes Carly do her job is super helpful imo.
It's meant to feel quite hectic at that stage of the game, remember theres nothing lost if you have bad sale days except the cafe's star rating and money earned (and cowe is dissapointed in you. thats the REAL reason to keep trying your best...)