After my surgery 2 weeks ago they gave me some vicodin. Which I really needed just to get out of bed and do "certain things". One pill truly did NOTHING to me so I woud take 2 (which the doc said was fine), and I would take 2 in the morning after I ate so I could just get out of bed, and 2 at night so I could fall asleep, and a few times I woke up in a lot of pain and had to take another 2 in the middle of the night. Well I stopped taking them a couple days ago because I was feeling fine, no pain. Since then I have been getting headaches, get sick to my stomach, and can't sleep at night. So I call my doctor today, and simply put, it is withdrawals from the vicodin. I never realized how bad the stuff was for you and how easy you can get hooked on it. I know everyones system isn't the same, but if you have to mess with the stuff, take it easy.