If you're fevered, you're agitated or overly excited about something. A group of middle school kids might have a fevered reaction to the news that their favorite band is in town.
While you can also use fevered to mean "hot" or "running a fever," it more commonly means "revved up" or "frenzied." A fevered imagination might turn spooky nighttime noises into a monster, and the arrival of a clown at a birthday party might cause both fevered excitement and terror from the guests. Fevered comes from fever, "high temperature," which has also meant "intense excitement" since the 16th century.