The flu is kicking into overdrive. 35 states are reporting widespread activity. 90% of those cases involve the H1N1 strain. Surprisingly, more than 60% of hospitalized patients are between the ages of 18 and 64 - that's almost twice as many as last year. The theory is that older Americans were exposed to similar strains in the past and may have built up more of an immunity. Flu is peaking, but sometimes it's tough to pinpoint what is making you feel under the weather. An easy way to tell if you have the flu is by spelling out the word "F.A.C.T.S."F - FeverA - AchesC - ChillsT - TirednessS - Sudden OnsetIf you're vomiting it's most likely not the flu, but some sort of stomach bug. Doctors say colds are quantified by a stuffy nose, sore throat, and maybe hoarseness. If you experience any kind of sickness, go to the doctor right away to avoid worsening symptoms. There are some medications to help ease the effects of influenza.