I don't think you would be addicted enough to have withdrawal symptoms after only taking it for a week..in my opinion anyways...Maybe you just feel gross! Listen to your body and if you feel too sick to stay at work go home...if you get home an dend up feeling fine thats ok too...Remember everyone has the right to be sick...and to go hom ebecause of it...If you feel you can stuick it out at work then do so as well...Having a headache can be really bad so I am sorry your feeling that way! I hope you feel better soon! and dont feel bads if you have to go home to rest!