PORTLAND, Maine (NEWS CENTER) -- If you've noticed a lot of people calling in sick at your work, there's a good reason for it: influenza. It is on the rise.

That's according to health expert Dr. Dora Anne Mills, vice president of clinical affairs at the University of New England vice president of Clinical Affairs. She says, in fact, the numbers of influenza cases are double this year from where they were last year.

As of last week, Maine had nearly 4,700 confirmed cases of the flu this season, compared to about 2,300 cases last season.

"The first thing is usually a fever with tremendous body ache where you just ache all over and you feel like you've been hit by a truck," Mills said. "You feel you can't get off the couch or out of bed."

According to the Maine Centers for Disease Control, nearly 60 percent of the positive flu tests reported to them occurred between the beginning of March and now.

"Most people don't get tested, but of the cases who get tested this year it looks like it's about double of what we had last year," she said.

And the former head of the Maine CDC is watching this influenza surge closely. She believes the numbers are even higher, and that most are cases that are preventable.

"One of the most contagious times is the day or two before you come down with the full symptoms," she said. "Usually some fever and body aches are the first thing and then some coughing."

Influenza is most dangerous for very young children, those with chronic illness or people over 50.

"Influenza is actually a pretty severe illness and something that people generally know, I mean, they're not well enough usually to go to work for a while," Mills said. "They're usually don't feel that they can get up off the couch or bed. They're pretty sick."

If you have body aches, fever or loss of appetite, Mills said the best thing you can do, for everyone, is to stay home and call your health care provider. And for those who had a flu shot: "The vaccine is a good match this year but it doesn't mean that people aren't sick with it right now."

The good news is, if you haven't had a flu shot yet, it's not too late, even in April. Mills said even getting it now will make a big difference if you do develop influenza.

To find a flu clinic near you, check out 211maine.org or the centers for disease control website.

The CDC also advises that you wash your hands often and cover your cough — always!