I have had a severe headache for 4 days now, it goes from my sinus passages to the back of my neck. Went to the doctor two days ago. He said it was sinusitis and gave me a 12 hr anti-biotic, told me take mucinex 2 every 12 hours, 1 allegra every 12 hours, and 2 alleve every 12 hours. I spaced them out so that I am not taking 5 pills at one time but rather over a 2 1/2 hr period. I also have chills, aches, low grade fever and felt like I was going to throw up, finally projectile vomitted and the stomach pain went away. I did not sleep at all yesterday. I felt better today even took a 2 hr nap. Took all my pills between 6:00 and 7:30 tonight. Took 2 of the lowest dose Xanax at 8:00 pm. It is now 4:00 am and no sleep for 2 nights in a row. Do I have the flu and sinusitis? The pressure and headache are starting to return.