For 10 days, those telegenic newlyweds, Trista Rehn and Ryan Sutter, whose Dec. 10 wedding broadcast on ABC was seen by 17.1 million people, enjoyed scuba diving, reading at leisure and napping on their relaxing honeymoon at the exclusive Turtle Island resort in Fiji, reports PEOPLE.

"Ryan was looking forward to the activities," says Trista, 31, "and I was looking forward to lying on the beach and getting a tan."

Yet upon their return to Vail, Colo., firefighter Ryan, usually a resilient and healthy guy, started to come down with something.

"I felt fine on the honeymoon and I felt fine over Christmas," says Sutter, 29. "In the last three days or so, my leg started to hurt where I got bit in Fiji, I think, by a spider."

This past Monday, he says, "We went to the doctor, and now I feel achy, I have a fever, and I think I'm coming down with the flu."

Not that Ryan will have a chance to rest. He and Trista faced a busy schedule all week, kicking off with a visit with Jay Leno on Tuesday's "Tonight" show and then hopping over Wednesday to the Playboy Mansion for publisher Hugh Hefner's New Year's Eve party.

Early Thursday, they'll be riding down Pasadena's Colorado Boulevard in the annual Tournament of Roses Parade, aboard the FTD float consisting of 100,000 roses. (Symbolic because Trista gave Ryan a rose on "The Bachelorette," to signify her love.)

Then, the couple drives a truck of their belongings from Rehn's Los Angeles apartment back to Vail.

"I hope I will be better," Ryan says. He'd better be – his fire-fighting resumes Jan. 8.