Hi I'm a teen feeling very sick. Over the past few days I've experienced sinus pressure serious headaches a 101 fever diarrhea nausea serious weakness and hot/cold flashes. I've been taking a tylenol a day and usually the symptoms wear off for past the time the tylenol should have worn off. But then they return. I've tried drinking water but that makes me feel ttwice as nauseous so I haven't eaten or drank much nor am I hungry/thirsty. Help?