If you are making a fuss, settle down! A fuss is a state of excitement, and it's usually about something not worth worrying or "fussing" about.
Most fusses are types of commotion. If someone makes a fuss, they're overexcited and in a tizzy over something, like someone who can't stop asking questions. Another fuss is angrier: you might say "What's the fuss?" if you hear two people yelling at each other. A fuss is also any kind of hubbub or whirlwind of activity, like a huge crowd swarming toward a sale. Parents tend to fuss over their children. Someone who fusses is worrying too much.